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TitlePagesPublicationCodeDatePublisherSystem (Setting)
Scenario O Apple TreeApr 2009Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Scenario O' Sleeper! Arise!139-146Softback Secrets of TibetCHA23129 2013 ChaosiumCall of Cthulhu (Classic)
Card O.E.S. RingSupport (F)Cards Lost RitesCT56 2012 Fantasy Flight GamesCall of Cthulhu LCG
Scenario Oath of Blood15-24Softback Blood BrothersCHA2329 1990 ChaosiumCall of Cthulhu (Classic)
Card Oath of the CovenSpell (F)Cards Rosemary's Babyn/aSelf PublishedMythos
Card Oath-bound ServantCharacter (U)Cards Eldritch Edition 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion EnforcerCharacter (C)Cards Arkham Edition 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion GunselsCharacter (C)Cards Arkham Edition 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion GunselsCharacter (F)Cards Arkham Edition Premium Starter Set 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion GunselsCharacter (F)Cards Arkham Edition Premium Starter Set 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion GunselsCharacter (F)Cards Arkham Edition Premium Starter Set 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion GunselsCharacter (F)Cards Arkham Edition Premium Starter Set 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion ThugCharacter (U)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion WarehouseSupport (F)Cards Eldritch Edition Premium Starter Set 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion WarehouseSupport (U)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card O'Bannion's Inner CouncilCharacter (F)Cards Denizens of the UnderworldCT62 2014 Fantasy Flight GamesCall of Cthulhu LCG
Card O'Bannion's LedgerSupport (F)Cards Words of PowerCT54 2012 Fantasy Flight GamesCall of Cthulhu LCG
Card Obed Marsh MemorialLocation (U)Cards New AeonCAO1311-1 1997 ChaosiumMythos
Scenario Obed's Forgotten Alliance2019Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Rules The Obelisk of Teg SuturlocOct 2020Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Scenario Obelisk: The Howling1PDF Obelisk: The Howling 2011 Self PublishedRisus
Background Object 318JB (Document #8366)1999Website delta-green.comn/aPagan PublishingCall of Cthulhu (Delta Green)
Rules Objets de Magie74-83Softback Unveiled ThreatsWDF23600 2011 WildFire GamesFramewerk (CthulhuTech)
Boardgame The Obligatory Cthulhu SetBoardgame The Obligatory Cthulhu SetAEG 5503 2013 Alderac Entertainment GroupSmash Up
Card Oblique StrategiesEvent (C)Cards Forgotten Cities 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card ObliterationAdventure (F)Website House of Tindalosn/aSelf PublishedMythos
Scenario Oblivion CircleSoftback More Tales of Terror PAG2105 2000 Pagan PublishingCall of Cthulhu (Classic)
Scenario Oblivion Circle2000Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Card Obscene ByakheeCharacter (F)Cards Spawn of Madness 2006 Fantasy Flight GamesCall of Cthulhu CCG
Card Obscene ByakheeCharacter (F)Cards Spawn of MadnessCT12e 2011 Fantasy Flight GamesCall of Cthulhu LCG
Card Obscene PolypCharacter (C)Cards Masks of Nyarlathotep 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card Obscure LinguistCharacter (F)Cards Aspirations of AscensionCT43 2011 Fantasy Flight GamesCall of Cthulhu LCG
Card Obscure Night of TormentAdventure (F)Website House of Tindalosn/aSelf PublishedMythos
Rules Obsequious ServantsSep 2020Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Card Obsessed Federal Agent/Obsessed Agent in a Mi-Go BraincaseInvestigator (C)Cards New AeonCAO1311-1 1997 ChaosiumMythos
Card Obsessive DetectiveCharacter (F)Cards The Twilight BeckonsCT40 2011 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive Elder ThingCharacter (F)Cards For the Greater GoodCT64 2015 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive InmateCharacter (F)Cards The Thing from the ShoreCT23 2009 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive InsomniacCharacter (F)Cards In Memory of DayCT27 2009 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive PlaywrightCharacter (F)Cards Murmurs of EvilCT35 2010 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive ResearchStory (F)Cards Secrets of ArkhamCT32 2010 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive SycophantCharacter (F)Cards The Breathing JungleCT49 2011 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive ZealotCharacter (F)Cards The Sleeper BelowCT63 2014 Fantasy Flight GamesCall of Cthulhu LCG
Card Obsessive/CompulsiveEvent (R)Cards LimitedCAO1300-1 1996 ChaosiumMythos
Scenario Obsideo Villa22-42Softback Malum UmbraCHA0353 2008 ChaosiumCall of Cthulhu (Invictus)
Background The Occult23-25Softback Green and Pleasant LandCHA2320 1987 ChaosiumCall of Cthulhu (Classic)
Background The Occult38-42Softback Mysteries of IrelandCHA0408 2012 ChaosiumCall of Cthulhu (Classic)
Rules Occult Books23-81Softback The Keeper's Companion Vol 1CHA2388 2000 ChaosiumCall of Cthulhu (Classic)
Rules Occult Books BibliographyFanzine The Unnamed3n/aSelf PublishedCall of Cthulhu (Classic)
Background Occult Engagement Protocols37-45Softback As Above, So BelowCB71209 2015 Cubicle 7Call of Cthulhu (Laundry)
Background Occult Groups (Minicults)16-24Softback Mystic AlliancesCHA0363 2009 ChaosiumCall of Cthulhu (Now)
Background Occult London72-77Softback The London GuidebookCHA2347 1996 ChaosiumCall of Cthulhu (Classic)
Scenario Occult Odds and EndsWebsite Occult Odds and Endsn/aSelf PublishedCall of Cthulhu (Classic)
Background Occult Organizations of the 1920's14-16Magazine Different Worlds45Mar 1987 ChaosiumCall of Cthulhu (Classic)
Background Occult Organizations of the 1920's14-16Fanzine The Hungry Maggot2Mar 1995 Self PublishedCall of Cthulhu (Classic)
Card Occult ShopSupport (R)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Rules Occult Tomes for CoCeZine Chaosium Digestv02n12Jul 1993 ChaosiumCall of Cthulhu (Classic)
Background An Occult Who's Who of the 1920s34-38Magazine Different Worlds43Jul 1986 ChaosiumCall of Cthulhu (Classic)
Scenario Occult WorksFanzine Manic Depressive1 1985 Self PublishedCall of Cthulhu (Classic)
Scenario The Occulted Light44-52Softback Before the FallCHA2377 1998 ChaosiumCall of Cthulhu (Classic)
Rules Occupations20-25PDF The Apocalypse MachinePELGT24 2011 Pelgrane PressTrail of Cthulhu
Rules Occupations23-27Softback Cthulhu ApocalypsePELGT40 2015 Pelgrane PressTrail of Cthulhu
Rules Occupations66-93Hardback Investigator's HandbookCHA23136 2015 ChaosiumCall of Cthulhu (Classic)
Rules Occupations38-45Softback Keeper's Resource Book and ScreenPELGT04 2008 Pelgrane PressTrail of Cthulhu
Background Occupations13-14Softback The London GuidebookCHA2347 1996 ChaosiumCall of Cthulhu (Classic)
Card Ocean CrawlersCharacter (F)Cards Call of Cthulhu The Card GameCT18 2008 Fantasy Flight GamesCall of Cthulhu LCG
Card Ocean CrawlersCharacter (U)Cards Masks of Nyarlathotep 2005 Fantasy Flight GamesCall of Cthulhu CCG
Scenario The Ocean of Sand84-101Softback Secrets of MoroccoCHA23105 2008 ChaosiumCall of Cthulhu (Classic)
Boardgame Octomaid Promo CardBoardgame Octomaid Promo CardJun 2016 Steve Jackson GamesMunchkin
Scenario Odd Behavior *80Softback Taint of MadnessCHA2354 1995 ChaosiumCall of Cthulhu (Classic)
Scenario The Odd Ingredient *89Softback Taint of MadnessCHA2354 1995 ChaosiumCall of Cthulhu (Classic)
Scenario Odder Than Odd18-21Magazine Polyhedron54Jul 1990 TSRCall of Cthulhu (Classic)
Card Ode to a ShopkeeperAdventure (F)Website House of Tindalosn/aSelf PublishedMythos
Scenario The Odin DiscSoftback Tales of Terror (II)PAG2102 1996 Pagan PublishingCall of Cthulhu (Classic)
Scenario Odin's Call72-94Softback Spirits & Dreams of the Viking AgeCHA0390 2010 ChaosiumCall of Cthulhu (Dark Ages)
Scenario OdontalgiaJun 2008Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Scenario Of Angels and Bones3-21Softback Halloween Horror 2CHA0333 2006 ChaosiumCall of Cthulhu (Classic)
Scenario Of Dreams and Dark Water177-207Softback Goatswood and Less Pleasant PlacesCHA2393 2001 ChaosiumCall of Cthulhu (Now)
Background Of Evill Sorceries Done in New England of Daemons in no Humane Shape60-64Magazine The Arkham Gazette3Oct 2015 Sentinel Hill PressCall of Cthulhu (Classic)
Scenario Of Grave Concern15-32PDF Monophobia1001 2010 Unbound PublishingCall of Cthulhu (Classic)
Card Of One MindSupport (R)Cards Forgotten Cities 2005 Fantasy Flight GamesCall of Cthulhu CCG
Scenario Of Sound Mind and Body1-23PDF Of Sound Mind and Body 2001 Self PublishedCall of Cthulhu (Gaslight)
Scenario Of Wrath and BloodPDF Of Wrath and BloodApr 2019 ChaosiumCall of Cthulhu (Classic)
Scenario Off Euclid Avenue2018Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario The Offal Truth2019Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Card Off-Duty PatrolmanCharacter (C)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card An Offer You Canít RefuseEvent (F)Cards The Order of the Silver TwilightCT33 2010 Fantasy Flight GamesCall of Cthulhu LCG
Card Office of Dr HillLocation (F)Cards Rosemary's Babyn/aSelf PublishedMythos
Card Office of Dr SapirsteinLocation (F)Cards Rosemary's Babyn/aSelf PublishedMythos
Card The Office of Dr. FreudLocation (U)Cards Expeditions of Miskatonic UniversityCAO1301-1 1996 ChaosiumMythos
Background The Office of Special Scientific Intelligence (Document #8417)1999Website delta-green.comn/aPagan PublishingCall of Cthulhu (Delta Green)
Card Officer GibsonCharacter (F)Cards For the Greater GoodCT64 2015 Fantasy Flight GamesCall of Cthulhu LCG
Card Officer NettlerAlly (F)Cards Rosemary's Babyn/aSelf PublishedMythos
Card Oh No! The Carpet!Event (F)Cards Rosemary's Babyn/aSelf PublishedMythos
Card Oh No, My Glasses!Event (F)Cards Scooby Doo Set 2Mar 1999 Self PublishedMythos
Scenario Oily Grave10-11Magazine The Unspeakable Oath14/15 1997 Pagan PublishingCall of Cthulhu (Classic)
Background Okeno, The Yellow City62-67Softback The Whisper Out of TimePZO90112 2016 Paizo PublishingPathfinder
Scenario Oklahoma104-125Softback The Two-Headed SerpentCHA23125 2017 ChaosiumCall of Cthulhu (Classic)
Card Ol' Lazy EyesCharacter (F)Cards Conspiracies of Chaos 2006 Fantasy Flight GamesCall of Cthulhu CCG
Card Ol' Lazy EyesCharacter (F)Cards Conspiracies of ChaosCT14e 2011 Fantasy Flight GamesCall of Cthulhu LCG
Card Olaus WormiusAlly (U)Cards Legends of the NecronomiconCAO1303-1 1996 ChaosiumMythos
Scenario Old Acquaintance19-30Softback Before the FallCHA2377 1998 ChaosiumCall of Cthulhu (Classic)
Card Old Arkham CemeteryLocation (C)Cards LimitedCAO1300-1 1996 ChaosiumMythos
Scenario The Old Believer2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Card The Old BellTome (F)Cards Scooby Doo Set 3n/aSelf PublishedMythos
Scenario Old Blood34-57PDF 40 Adventures for Call of Cthulhu 2002 Self PublishedCall of Cthulhu (Now)
Scenario Old Blood1-23PDF Old Blood 1996 Self PublishedCall of Cthulhu (Now)
Scenario Old Blood20-37eZine Opifex Bimonthly5 1996 Self PublishedCall of Cthulhu (Now)
Card Old Brick PowderhouseLocation (C)Cards DreamlandsCAO1307-1 1997 ChaosiumMythos
Card The Old CemetaryLocation (F)Cards Sesqua Valleyn/aSelf PublishedMythos
Scenario The Old ChurchSoftback Tales of Terror (I) 1990 Pagan PublishingCall of Cthulhu (Classic)
Scenario The Old Church17-18PDF Tales of Terror (III)n/aSelf PublishedCall of Cthulhu (Classic)
Scenario The Old Church1990Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Card Old City BazaarSupport (R)Cards Eldritch Edition 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card Old Congregational ChurchLocation (F)Cards UnlimitedCAO1306-1 1997 ChaosiumMythos
Scenario The Old Cottage2003Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Scenario The Old Damned House116-147Softback Mansions of MadnessCHA23110 2007 ChaosiumCall of Cthulhu (Classic)
Scenario The Old Dark House60-67Softback Alone on HalloweenPAG1000 1992 Pagan PublishingCall of Cthulhu (Classic)
Card Old FarmhouseLocation (F)Cards Scooby Doo Set 1n/aSelf PublishedMythos
Scenario Old Fellow That Bunyip71-91Softback Terror AustralisCHA2319 1987 ChaosiumCall of Cthulhu (Classic)
Scenario An Old Friend2002Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Card The Old GibbetLocation (F)Cards UnlimitedCAO1306-1 1997 ChaosiumMythos
Rules The Old Grimoire77-96Softback Cthulhu Dark AgesCHA2398 2004 ChaosiumCall of Cthulhu (Dark Ages)
Card Old Gypsy WomanAlly (F)Cards Scooby Doo Set 1n/aSelf PublishedMythos
Rules Old HagsOct 2005Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Scenario The Old HouseeZine Nightwatch1Nov 1992 Self PublishedCall of Cthulhu (Classic)
Rules The Old Lady7Magazine Protodimension5Sum 2010 Kinstaff MediaCall of Cthulhu (Now) , Dark Conspiracy
Card Old Man GrisbyAlly (F)Cards Scooby Doo Set 3n/aSelf PublishedMythos
Card Old Man Grisby's PlaceLocation (F)Cards Scooby Doo Set 3n/aSelf PublishedMythos
Scenario The Old Man of DamascusSoftback The Old Man of DamascusSKP0701 2007 Skirmisher PublishingCall of Cthulhu (Strange Aeons)
Card Old Man of the WoodsCharacter (F)Cards The Order of the Silver TwilightCT33 2010 Fantasy Flight GamesCall of Cthulhu LCG
Scenario Old Man TompkinsPDF Old Man TompkinsJun 2019 ChaosiumCall of Cthulhu (Classic)
Card Old Man WhateleyAlly (R)Cards Expeditions of Miskatonic UniversityCAO1301-1 1996 ChaosiumMythos
Card Old MausoleumLocation (F)Cards Scooby Doo Set 2Mar 1999 Self PublishedMythos
Card Old Mill RuinsLocation (C)Cards Expeditions of Miskatonic UniversityCAO1301-1 1996 ChaosiumMythos
Card Old Mine StorehouseLocation (F)Cards Scooby Doo Set 2Mar 1999 Self PublishedMythos
Card The Old NeighborhoodSupport (R)Cards Masks of Nyarlathotep 2005 Fantasy Flight GamesCall of Cthulhu CCG
Boardgame Old OneBoardgame Old One 2020 Grimlord GamesThe Everrain
Background Old Ones and Old Gods72-75Softback Cthulhu Britannica: FolkloreCB7351 2012 Cubicle 7Call of Cthulhu (Classic)
Scenario Old Ones Anonymous2017Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Card Old SawmillLocation (F)Cards Scooby Doo Set 1n/aSelf PublishedMythos
Card Old Sea DogCharacter (F)Cards The Path to Y'ha-nthleiCT24 2009 Fantasy Flight GamesCall of Cthulhu LCG
Scenario The Old Serpent29-36Magazine Role Player Independent12Nov 1993 Symbiosis PublishingCall of Cthulhu (Classic)
Scenario The Old Serpent19-33Magazine Role Player Independent13Dec 1993 Symbiosis PublishingCall of Cthulhu (Classic)
Scenario The Old SerpentMagazine Role Player Independent14Feb 1994 Symbiosis PublishingCall of Cthulhu (Classic)
Background Old Sins, Long Shadows4-15Softback Shadows of AtlantisMUH01022CS 2015 Modiphius EntertainmentCall of Cthulhu (Achtung!) , Savage Worlds (Achtung!)
Scenario The Old Straight TrackSoftback Tales of Terror (I) 1990 Pagan PublishingCall of Cthulhu (Classic)
Scenario The Old Straight Track14PDF Tales of Terror (III)n/aSelf PublishedCall of Cthulhu (Classic)
Scenario The Old Straight Track1990Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Rules Old West Investigators9-32Softback Down Darker TrailsCHA23151 2017 ChaosiumCall of Cthulhu (Wild West)
Card Old Witch's ShackLocation (F)Cards Scooby Doo Set 1n/aSelf PublishedMythos
Card Old Woman of the Enchanted WoodAlly (U)Cards DreamlandsCAO1307-1 1997 ChaosiumMythos
Rules OlitiauFeb-2021Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Boardgame Oliver GraysonBoardgame Oliver Grayson 2011 Fantasy Flight GamesArkham Horror
Card Omar Shakti, Ageless WizardCharacter (R)Cards Eldritch Edition 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card Omega AlumnusCharacter (F)Cards Spawn of Madness 2006 Fantasy Flight GamesCall of Cthulhu CCG
Card Omega AlumnusCharacter (F)Cards Spawn of MadnessCT12e 2011 Fantasy Flight GamesCall of Cthulhu LCG
Boardgame Omega Master RulebookBoardgame Omega Master RulebookCW-E12 2017 Petersen GamesCthulhu Wars
Boardgame Omens of IceBoardgame Omens of IceSL17 2016 Fantasy Flight GamesElder Sign
Boardgame Omens of the DeepBoardgame Omens of the DeepSL19 2017 Fantasy Flight GamesElder Sign
Boardgame Omens of the PharaohBoardgame Omens of the PharaohSL20 2018 Fantasy Flight GamesElder Sign
Scenario On a Bank by MoonlightSoftback A Cable's Length From Shore/On a Bank by MoonlightPELGDGCC01 2018 Pelgrane PressCall of Cthulhu (Delta Green)
Scenario On a Lonely Road18-19PDF Lux in TenebrasMRP0006 2011 Miskatonic River PressCall of Cthulhu (Invictus)
Rules On Becoming an Investigator6-47Softback 1920s Investigator's Companion Vol. IICHA2346 1994 ChaosiumCall of Cthulhu (Classic)
Scenario On Borrowed Time49-61Softback As Above, So BelowCB71209 2015 Cubicle 7Call of Cthulhu (Laundry)
Card On Byakhee WingsEvent (R)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Rules On Conventions53-64Softback De ProfundisCB71401 2010 Cubicle 7De Profundis
Background On CultistsB:10-12Boxed Call of CthulhuCHA2301-X 1983 ChaosiumCall of Cthulhu (Classic)
Background On Cultists104-106Hardback Call of CthulhuCHA2317-H 1986 ChaosiumCall of Cthulhu (Classic)
Rules On Gaming in Averoigne58-60Magazine Worlds of Cthulhu1Aug 2004 Pegasus PressCall of Cthulhu (Dark Ages)
Card On IceEvent (R)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Scenario On Ilkla Moor Baht'at93-95Softback Lovecraftesque 2016 Black ArmadaLovecraftesque
Rules On Keeping Masks of Nyarlathotep20-28Hardback The Masks of Nyarlathotep Companion (Limited)60-MONC-08 2016 Sixtystone PressCall of Cthulhu (Classic)
Rules On Keeping Masks of Nyarlathotep20-28Softback The Masks of Nyarlathotep Companion (Unlimited)60-MONC-03 (?) 2016 Sixtystone PressCall of Cthulhu (Classic)
Background On the Anti-Libertarian Nature of Cthulhu Worship12-13Magazine Valkyrie1Sep 1994 Partizan PressCall of Cthulhu (Classic)
Scenario On the Banks of the OhioPDF On the Banks of the Ohio 2019 ChaosiumCall of Cthulhu (Classic)
Background On the EdgeeZine Chaosium Digestv21n11Sep 1997 ChaosiumMythos
Card On the EdgeAdventure (F)PDF Eric Johnson Mythos Collectionn/aSelf PublishedMythos
Card On the EdgeAdventure (R)Cards LimitedCAO1300-1 1996 ChaosiumMythos
Background On The EdgeWebsite Robo's Mythos CCG Web Pagen/aSelf PublishedMythos
Card On the GriftEvent (U)Cards Eldritch Edition 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card On the LamEvent (F)Cards Arkham Edition Premium Starter Set 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card On the LamEvent (F)Cards Denizens of the UnderworldCT62 2014 Fantasy Flight GamesCall of Cthulhu LCG
Card On the Mean StreetsSupport (U)Cards Forbidden Relics 2004 Fantasy Flight GamesCall of Cthulhu CCG
Background On the Moon and In the SeaeZine Chaosium Digestv21n03Aug 1997 ChaosiumMythos
Background On the Name 'Dagon'20-22Magazine The Arkham Gazette2Nov 2013 Sentinel Hill PressCall of Cthulhu (Classic)
Background On the Road Again572-586Hardback The Masks of Nyarlathotep Companion (Limited)60-MONC-08 2016 Sixtystone PressCall of Cthulhu (Classic)
Background On the Road Again444-457Softback The Masks of Nyarlathotep Companion (Unlimited)60-MONC-03 (?) 2016 Sixtystone PressCall of Cthulhu (Classic)
Scenario On The Road to Nowhere1999Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Card On the RunEvent (F)Cards The Unspeakable PagesCT57 2012 Fantasy Flight GamesCall of Cthulhu LCG
Card On the TakeSupport (F)Cards For the Greater GoodCT64 2015 Fantasy Flight GamesCall of Cthulhu LCG
Scenario On the Threshold of Chapel Perilous *PDF The Once and Future King 1999 Self PublishedCall of Cthulhu (Classic)
Background On the Ubiquity of Cthulhu5-6Softback Fragments of FearCHA2310 1985 ChaosiumCall of Cthulhu (Classic)
Scenario On the Wings of Madness5-17Softback Whispers from the AbyssT-4 1984 Theatre of the Mind EnterprisesCall of Cthulhu (Classic)
Background On Ye Invitation and Leave-Taking of the Quiet One (Document #8187)1998Website delta-green.comn/aPagan PublishingCall of Cthulhu (Delta Green)
Background The Once and Future King57-60Softback The Golden DawnPAG1004 1996 Pagan PublishingCall of Cthulhu (Gaslight)
Scenario A Once and Future King11-16Magazine The Whisperer1Sum 1999 Severn Valley PressCall of Cthulhu (Classic)
Scenario Once Bitten1996Website Roleplay, What, Who, Why and Where?n/aSelf PublishedCall of Cthulhu (Classic)
Scenario Once in a Lifetime2018Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Fiction Once in a Lifetime52-53Softback Vade MecumWDF23001 2008 WildFire GamesFramewerk (CthulhuTech)
Background Once Risen, Twice Shy17Magazine White Dwarf66Jun 1985 Games WorkshopCall of Cthulhu (Classic)
Card One Dark and Stormy NightAdventure (C)Cards LimitedCAO1300-1 1996 ChaosiumMythos
Rules One Doesn't Say Its NameFeb-2021Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Scenario One For the Money4-37Softback One for the MoneyPELGOC04D 2017 Pelgrane PressGumshoe (Cthulhu Confidential)
Card One for the RoadSupport (R)Cards Forgotten Cities 2005 Fantasy Flight GamesCall of Cthulhu CCG
Scenario One Friday NightPDF One Friday NightAug 2020 ChaosiumCall of Cthulhu (Now)
Scenario One in Darkness75-86Softback The Great Old OnesCHA2321 1989 ChaosiumCall of Cthulhu (Classic)
Scenario One Less GravePDF One Less GraveNov 2020 ChaosiumCall of Cthulhu (Classic)
Rules One Man's Meat: Making the most of Poision in Role Playing Games52-54Magazine The Adventurer6Jan 1987 Mersey Leisure PublishingCall of Cthulhu (Classic)
Scenario One of our Agents is Missing!Website Delta Green Anomaliesn/aSelf PublishedCall of Cthulhu (Delta Green)
Background One of the CircleeZine Chaosium Digestv21n04Aug 1997 ChaosiumMythos
Card One of the CircleAdventure (U)Cards Cthulhu RisingCAO1302-1 1996 ChaosiumMythos
Card One of the ThousandCharacter (F)Cards Perilous TrialsCT41 2011 Fantasy Flight GamesCall of Cthulhu LCG
Scenario One of Us1-39PDF One of Us 2008 Self PublishedCall of Cthulhu (Classic)
Boardgame One of Us Becomes and Evil God!Boardgame One of Us Becomes and Evil God! 2017 AHCOne of Us Becomes and Evil God!
Rules One Page Sanity LossPDF One Page Sanity LossApr 2020 ChaosiumCall of Cthulhu (Classic)
Card One Small StepAdventure (U)Cards New AeonCAO1311-1 1997 ChaosiumMythos
Scenario One Starry NightMagazine d infinity3May 2012 Skirmisher PublishingCall of Cthulhu (Classic)
Scenario One Step Beyond308-313Softback Secrets of JapanCHA2392 2005 ChaosiumCall of Cthulhu (Classic)
Fiction One Step Forward8-11Softback Burning HorizonWDF23301 2011 WildFire GamesFramewerk (CthulhuTech)
Rules The One(s) That Got AwaySep 2020Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Card One-In-AllSupport (F)Cards The Key and the GateCT60 2013 Fantasy Flight GamesCall of Cthulhu LCG
Card One-Way TicketSupport (R)Cards Forgotten Cities 2005 Fantasy Flight GamesCall of Cthulhu CCG
Rules OniOct 2019Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Background ONI Project PUZZLE118-120Softback Delta Green Eyes OnlyPAG1013 2007 Pagan PublishingCall of Cthulhu (Delta Green)
Background ONI Project PUZZLE40-45Softback Delta Green Eyes Only Vol 3: Project RainbowPAG2106 2000 Pagan PublishingCall of Cthulhu (Delta Green)
Unknown Only After Dark23-42Magazine Book of Dark Wisdom1Sum 2003 Elder Sign PressCall of Cthulhu (Classic)
Boardgame Onslaught 3 Stretch Goal BoxBoardgame Onslaught 3 Stretch Goal BoxCW-E20 2019 Petersen GamesCthulhu Wars
Scenario Onto the Ice98-113Softback Beyond the Mountains of MadnessCHA2380 1999 ChaosiumCall of Cthulhu (Classic)
Scenario Onward to Endurance73-84Softback Walker in the WastesPAG1002 1994 Pagan PublishingCall of Cthulhu (Classic)
Card The Onyx TempleLocation (U)Cards DreamlandsCAO1307-1 1997 ChaosiumMythos
Scenario The Ooze112-127Softback Cthulhu LiveCHA6502 1997 ChaosiumCall of Cthulhu (Classic)
Scenario OP EV ICE2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Card The Opal ThroneLocation (C)Cards DreamlandsCAO1307-1 1997 ChaosiumMythos
Scenario Opeation DROPOUT2019Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario OPEATION WITCH-HUNT2017Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Card Open for InspectionSupport (F)Cards Call of Cthulhu The Card GameCT18 2008 Fantasy Flight GamesCall of Cthulhu LCG
Card Open for InspectionSupport (U)Cards Masks of Nyarlathotep 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card Open GateEvent (R)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card Open GraveSupport (F)Cards The Thing from the ShoreCT23 2009 Fantasy Flight GamesCall of Cthulhu LCG
Card The Opened DoorStory (F)Cards The Shifting SandsCT47 2011 Fantasy Flight GamesCall of Cthulhu LCG
Card Opener of the GateCharacter (F)Cards Ancient HorrorsCT17 2008 Fantasy Flight GamesCall of Cthulhu LCG
Boardgame Opener of the WayBoardgame Opener of the WayCW-F1 2015 Petersen GamesCthulhu Wars
Scenario Opening Act: The April Mix61-77Softback Strange SongsCHA0315 2005 ChaosiumCall of Cthulhu (Now)
Card Opening NightStory (F)Cards Call of Cthulhu The Card GameCT18 2008 Fantasy Flight GamesCall of Cthulhu LCG
Card Opening NightConspiracy (F)Cards The Mark of MadnessCT66 2015 Fantasy Flight GamesCall of Cthulhu LCG
Scenario Opening Night19-27Softback Tatters of the KingCHA23104 2006 ChaosiumCall of Cthulhu (Classic)
Card The opening of Every GateEvent (P)Cards Eldritch Edition Promo 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card Opening the Limbo GateEvent (F)Cards Call of Cthulhu The Card GameCT18 2008 Fantasy Flight GamesCall of Cthulhu LCG
Card Opening the Limbo GateEvent (R)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card Opening the Third EyeEvent (F)Cards Eldritch Edition Premium Starter Set 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card Opening the Third EyeEvent (C)Cards Unspeakable Tales 2004 Fantasy Flight GamesCall of Cthulhu CCG
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Scenario Operation COLD BOOK/Against All Odds2018Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
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Scenario Operation Header122-148Softback World War Cthulhu: Cold War - Covert ActionsCB71972 2017 Cubicle 7Call of Cthulhu (Cold War)
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Card Operation NemesisAdventure (C)Cards New AeonCAO1311-1 1997 ChaosiumMythos
Scenario Operation NITEFIREWebsite Delta Green Anomaliesn/aSelf PublishedCall of Cthulhu (Delta Green)
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Scenario Operation Pastel Weather2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Background Operation PEA GREEN (Document #8435a)1999Website delta-green.comn/aPagan PublishingCall of Cthulhu (Delta Green)
Background Operation PEA GREEN (Document #8435b)1999Website delta-green.comn/aPagan PublishingCall of Cthulhu (Delta Green)
Scenario Operation PEAK DHOLE or Camp Fairfield2018Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
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Scenario Operation SPRING GOOSE *2006Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario Operation STOP REPO *2017Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario Operation Stop Repo *51-54Magazine The Unspeakable Oath25Jul 2018 Pagan PublishingDelta Green
Scenario Operation TIN MANSION / Shrunken City '682020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
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Scenario Operation Traitor's Gate2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
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Scenario OPERATION WOODWORK2017Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario Operation: Shared Brilliance2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario Operation: Shower Gel2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Background Operative KRYPTERWebsite Delta Green Plausible Deniabilityn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario Ophelia Rising70-78Hardback Hudson and Brand, Inquiry Agents of the Obscure3004 2017 Stygian FoxCall of Cthulhu (Gaslight)
Card Ophidian BlightEvent (F)Cards Curse of the Jade EmperorCT48 2011 Fantasy Flight GamesCall of Cthulhu LCG
Card Opium FiendCharacter (C)Cards Eldritch Edition 2005 Fantasy Flight GamesCall of Cthulhu CCG
Card Optic WarehouseSupport (F)Cards The Wailer BelowCT37 2010 Fantasy Flight GamesCall of Cthulhu LCG
Background Optics79-80Softback The Gaslight Equipment CatalogueCHA0319 2005 ChaosiumCall of Cthulhu (Gaslight)
Rules Optional Rules for the Old West45-52Softback Down Darker TrailsCHA23151 2017 ChaosiumCall of Cthulhu (Wild West)
Background Or, A Dragon Passant, Sable32-35Magazine The Last Province4Jun 1993 Last Province PublishingCall of Cthulhu (Classic)
Novelty Orange and Ebola Sanity TracksPDF Eric Johnson Mythos Collectionn/aSelf PublishedMythos
Rules The OrdentaniOct 2019Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Invictus)
Scenario Order of the Stone61eZine Fictional Reality12Jun 2003 Self PublishedCall of Cthulhu (Classic)
Scenario The Order of the Sword of Saint Jerome35-48Softback The AbbeyCHA0088 2004 ChaosiumCall of Cthulhu (Dark Ages)
Scenario The Organ Doner2003Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Background Organisations34-41Softback Jovian NightmaresCHA0367 2009 ChaosiumCall of Cthulhu (Rising)
Scenario Organism 46bNov 2019Website Reckoning of the Deadn/aSelf PublishedCall of Cthulhu (Now)
Background Organizations58-66Softback The Armitage FilesPELGT10 2010 Pelgrane PressTrail of Cthulhu
Background Organizations372-405PDF Raiders of R'lyeh Gamemaster's Guide and Complete Rules 2017 Self PublishedRaiders of R'lyeh
Card The Orient ExpressSupport (U)Cards Arkham Edition 2004 Fantasy Flight GamesCall of Cthulhu CCG
Background The Orient ExpressA:11-18Boxed Horror on the Orient ExpressCHA23130 2014 ChaosiumCall of Cthulhu (Classic)
Background The Orient ExpressA:1-4Boxed Horror on the Orient ExpressCHA2331-X 1991 ChaosiumCall of Cthulhu (Classic)
Novelty Orient Express TicketsPDF Orient Express TicketsSep 2018 ChaosiumCall of Cthulhu (Classic)
Background Orientation6-13Softback Arkham UnveiledCHA2325 1990 ChaosiumCall of Cthulhu (Classic)
Rules Orientation9-17Softback Call of CthulhuCHA2336 1992 ChaosiumCall of Cthulhu (Classic)
Background Orientation9-15Softback The Compact Arkham UnveiledCHA2356 1995 ChaosiumCall of Cthulhu (Classic)
Rules The Original, the Eternal, the UndyingSep 2020Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Card Orlach Lives!Adventure (F)Website House of Tindalosn/aSelf PublishedMythos
Card Orne Formula & DiagramsArtifact (R)Cards Cthulhu RisingCAO1302-1 1996 ChaosiumMythos
Background Ornery Octal10-11Softback Targets of AcquisitionCB61202 2015 Cubicle 7Call of Cthulhu (Laundry)
Card Orne's BlackSpell (C)Cards Legends of the NecronomiconCAO1303-1 1996 ChaosiumMythos
Scenario Orono Man: The Scientific Investigation of an Atypical Inhumation2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Scenario Orphan School HorrorPDF Orphan School Horrorcr3005i 2017 Cthulhu RebornCall of Cthulhu (Convicts)
Card Osborn's General StoreLocation (C)Cards Expeditions of Miskatonic UniversityCAO1301-1 1996 ChaosiumMythos
Scenario The Osbrook House120-126Softback Walker in the WastesPAG1002 1994 Pagan PublishingCall of Cthulhu (Classic)
Card Oscar JamesAlly (F)Cards Sesqua Valleyn/aSelf PublishedMythos
Scenario The Osiris Club161-186Softback Cthulhu Live: Shades of Gray0008 2000 Fantasy Flight GamesCall of Cthulhu (Classic)
Scenario Oswalt's Dolls2020Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Card OtaheiteLocation (C)Cards Cthulhu RisingCAO1302-1 1996 ChaosiumMythos
Card The Other Gods IAdventure (F)Website House of Tindalosn/aSelf PublishedMythos
Card The Other Gods IIAdventure (F)Website House of Tindalosn/aSelf PublishedMythos
Background Other Investigator Organisations36-37Softback World War Cthulhu: LondonCB71941 2016 Cubicle 7Call of Cthulhu (WWII)
Background Other Locations32-33Softback Jovian NightmaresCHA0367 2009 ChaosiumCall of Cthulhu (Rising)
Background Other Mysteries of the Dawn61-62Softback The Golden DawnPAG1004 1996 Pagan PublishingCall of Cthulhu (Gaslight)
Background Other OccupationsB:10Boxed Call of CthulhuCHA2301-X 1983 ChaosiumCall of Cthulhu (Classic)
Rules Other Occupations104Hardback Call of CthulhuCHA2317-H 1986 ChaosiumCall of Cthulhu (Classic)
Card The Other PathStory (F)Cards Call of Cthulhu The Card GameCT18 2008 Fantasy Flight GamesCall of Cthulhu LCG
Rules The Other Place20-28Softback God Game BlackCB71207 2013 Cubicle 7Call of Cthulhu (Laundry)
Background The Other Secret War49-59Softback Keeper's Guide to the Secret WarMPS01032CS 2013 Modiphius EntertainmentCall of Cthulhu (Achtung!) , Savage Worlds (Achtung!)
Background Other Senses18-19Magazine Different Worlds28Apr 1983 ChaosiumCall of Cthulhu (Classic)
Background The Otherworld13-20Softback Spirits & Dreams of the Viking AgeCHA0390 2010 ChaosiumCall of Cthulhu (Dark Ages)
Card The OubliettesSupport (F)Cards The Order of the Silver TwilightCT33 2010 Fantasy Flight GamesCall of Cthulhu LCG
Rules Ouch! The Messy Problem of PC Injury4-?eZine Demonground12Jun 2001 Self PublishedCall of Cthulhu (Classic)
Scenario Our Ladies of Sorrow126-131Softback Our Ladies of SorrowMRP0005 2009 Miskatonic River PressCall of Cthulhu (Now)
Scenario Out For BloodSoftback More Tales of Terror PAG2105 2000 Pagan PublishingCall of Cthulhu (Classic)
Scenario Out of Mind..Out of Time...2014Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Card Out Of My MindAdventure (R)Cards New AeonCAO1311-1 1997 ChaosiumMythos
Card Out of Season MonsoonEvent (F)Cards Shadow of the MonolithCT52 2012 Fantasy Flight GamesCall of Cthulhu LCG
Scenario Out of the Ages86-104Magazine Worlds of Cthulhu5Jan 2007 Pegasus PressCall of Cthulhu (Now)
Scenario Out of the BlueSoftback More Tales of Terror PAG2105 2000 Pagan PublishingCall of Cthulhu (Classic)
Scenario Out of the Celtic Twilight46-57Softback Whispers in the Dark0003Oct 1993 Triad EntertainmentsCall of Cthulhu (Classic)
Background Out of the Dark Realms in Between112-115Magazine Worlds of Cthulhu1Aug 2004 Pegasus PressCall of Cthulhu (Classic)
Card Out of the DarknessEvent (F)Cards The CacophonyCT39 2010 Fantasy Flight GamesCall of Cthulhu LCG
Scenario Out of the Depths140-156PDF 40 Adventures for Call of Cthulhu 2002 Self PublishedCall of Cthulhu (Now)
Scenario Out of the Depths1-17PDF Out of the Depths 1992 Self PublishedCall of Cthulhu (Now)
Scenario Out of the Mouths of BabesFanzine Serendipity's Circle11n/aSelf PublishedCall of Cthulhu (Now)
Scenario Out of the Mouths of Babes and ChildrenSoftback More Tales of Terror PAG2105 2000 Pagan PublishingCall of Cthulhu (Classic)
Unknown Out of the Ordinary7-?Magazine Shadis41Oct 1997 Alderac Entertainment GroupCall of Cthulhu (Classic)
Scenario Out of the PastPDF Out of the PastMay 2019 ChaosiumCall of Cthulhu (Classic)
Card Out of Your HeadAdventure (F)PDF Eric Johnson Mythos Collectionn/aSelf PublishedMythos
Card Outback PoacherCharacter (F)Cards Shadow of the MonolithCT52 2012 Fantasy Flight GamesCall of Cthulhu LCG
Card OutbreakAdventure (U)Cards New AeonCAO1311-1 1997 ChaosiumMythos
Rules Outbreak Generator Charts54-56Magazine Protodimension4Spr 2010 Kinstaff MediaCall of Cthulhu (Now)
Scenario An Outbreak of CancerSoftback Tales of Terror (I) 1990 Pagan PublishingCall of Cthulhu (Classic)
Scenario An Outbreak of Cancer13-14PDF Tales of Terror (III)n/aSelf PublishedCall of Cthulhu (Classic)
Scenario An Outbreak of Cancer1990Website talesofterror.netn/aSelf PublishedCall of Cthulhu (Classic)
Background The Outer Boroughs99-132Softback Secrets of New YorkCHA23103 2005 ChaosiumCall of Cthulhu (Classic)
Background The Outer Order Curriculum39-43Softback The Golden DawnPAG1004 1996 Pagan PublishingCall of Cthulhu (Gaslight)
Scenario An Outer Space Adventure IdeaeZine Chaosium Digestv07n08Sep 1994 ChaosiumCall of Cthulhu (Now)
Background The Outlook Group106-123Softback Delta Green CountdownPAG1008 1999 Pagan PublishingCall of Cthulhu (Delta Green)
Background Outlying Areas127-136Softback Secrets of Los AngelesCHA23111 2007 ChaosiumCall of Cthulhu (Classic)
Card OutmaneuveredEvent (F)Cards Denizens of the UnderworldCT62 2014 Fantasy Flight GamesCall of Cthulhu LCG
Scenario The Outpost of Progress73-78Softback Secrets of the CongoCHA0387 2010 ChaosiumCall of Cthulhu (Classic)
Background The Outside47-57Softback The Cruel Empire of Tsan ChanCHA0397 2010 ChaosiumCall of Cthulhu (Strange Aeons: 5000AD)
Scenario Outside in the Cold Distance2018Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Rules Outside the Laundry98-113Softback Agent's HandbookCB71203 2011 Cubicle 7Call of Cthulhu (Laundry)
Card The OutsiderAdventure (R)Cards LimitedCAO1300-1 1996 ChaosiumMythos
Rules The Outsider WithinOct 2020Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Rules Outsiders and Psychic Abilities147-172Softback Cthulhu LiveSKP0602 2006 Skirmisher PublishingCall of Cthulhu (Classic)
Scenario Overdue47-52Magazine Bayt al Azif1Oct 2018 Bayt al Azif IncCall of Cthulhu (Classic)
Card Over-equipped InvestigatorCharacter (U)Cards Eldritch Edition 2005 Fantasy Flight GamesCall of Cthulhu CCG
Rules The Overlooked & The UnclearWebsite House of Tindalosn/aSelf PublishedMythos
Scenario Overshadowed2016Website The Fairfield Projectn/aSelf PublishedCall of Cthulhu (Delta Green)
Novelty Oversized 3-5 Player Earth MapNovelty Oversized 3-5 Player Earth MapCW-M13 2018 Petersen GamesCthulhu Wars
Background Overview of Extrico Tabula5-15Softback Extrico TabulaCHA0354 2008 ChaosiumCall of Cthulhu (Invictus)
Background An Overview of Ireland 1919-19306-9Softback Mysteries of IrelandCHA0408 2012 ChaosiumCall of Cthulhu (Classic)
Background Overview of Malum Umbra5-11Softback Malum UmbraCHA0353 2008 ChaosiumCall of Cthulhu (Invictus)
Rules An Overview of the Game5-10PDF Call of Cthulhu 7th Edition Quick StartCHA23131 2013 ChaosiumCall of Cthulhu (Classic)
Rules Overview of the GameA:3-5Boxed Call of Cthulhu Starter SetCHA23158-X 2018 ChaosiumCall of Cthulhu (Classic)
Card Overwhelmed by NightmaresEvent (U)Cards Forbidden Relics 2004 Fantasy Flight GamesCall of Cthulhu CCG
Card Overworked BureaucratCharacter (F)Cards For the Greater GoodCT64 2015 Fantasy Flight GamesCall of Cthulhu LCG
Card Overworked Graduate StudentCharacter (F)Cards Seekers of KnowledgeCT59 2012 Fantasy Flight GamesCall of Cthulhu LCG
Card Overworked Telephone Operator/Falsely Imprisoned ConvictInvestigator (F)Cards DreamlandsCAO1307-1 1997 ChaosiumMythos
Card Overzealous InitiateCharacter (F)Cards Call of Cthulhu The Card GameCT18 2008 Fantasy Flight GamesCall of Cthulhu LCG
Card Overzealous InitiateCharacter (C)Cards Eldritch Edition 2005 Fantasy Flight GamesCall of Cthulhu CCG
Rules The OwlmanOct 2014Website shoggoth.netn/aSelf PublishedCall of Cthulhu (Classic)
Scenario The Oxford ArticlesPDF The Oxford ArticlesAug 2021 ChaosiumCall of Cthulhu (Strange Aeons: 1953)
Card Ozzy OrneAlly (C)Cards New AeonCAO1311-1 1997 ChaosiumMythos