| Title | Pages | Publication | Code | Date | Publisher | System (Setting) |
|---|
 U Mad Bro? | | U Mad Bro? | | 2016 | Prettiest Princess Games | U Mad Bro?
| |
 U.S. Coastguard Station | Location (C) |  New Aeon | CAO1311-1 | 1997 | Chaosium | Mythos
| |
| U.S. Naval Installation | Location (F) | Rosemary's Baby | | n/a | Self Published | Mythos
| |
 U.S. Special Operations Command | 1999 |  delta-green.com | | n/a | Pagan Publishing | Call of Cthulhu (Delta Green)
| |
 U.X.O * | 2007 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
| |
 Ubbo-Sathla | |  Dagon | 4 | Oct 1984 | Self Published | Call of Cthulhu (Classic)
| |
| Ubbo-Sathla Promo Card | | Ubbo-Sathla Promo Card | | 2015 | Fantasy Flight Games | Elder Sign
| |
| U-Boat | Event (U) | Cthulhu Rising | CAO1302-1 | 1996 | Chaosium | Mythos
| |
| UFO | Event (U) | New Aeon | CAO1311-1 | 1997 | Chaosium | Mythos
| |
| Uisge Beatha * | 197-225 |  Shadows Over Scotland | CB7353 | 2011 | Cubicle 7 | Call of Cthulhu (Classic)
| |
 Ulms | 16-18 |  Book of Dark Wisdom | 1 | Sum 2003 | Elder Sign Press | Call of Cthulhu (Classic)
| |
| Ulthar | 248-271 | The Sense of the Sleight of Hand Man | APU8001 | 2013 | Arc Dream Publishing | Call of Cthulhu (Dreamlands)
| |
| Ulthar and Beyond | 106-121 | Spawn of Azathoth | CHA23101 | 2005 | Chaosium | Call of Cthulhu (Classic)
| |
| Ulthar and Beyond | B:36-44 |  Spawn of Azathoth | CHA2316-X | 1986 | Chaosium | Call of Cthulhu (Classic)
| |
| Ultima Thule | Support (F) | Seekers of Knowledge | CT59 | 2012 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Ultima Thule | |  Ultima Thule | | Jun 2020 | Chaosium | Call of Cthulhu (Classic)
| |
| Ultima Thule, Beyond Which Nothing | Support (R) | Forgotten Cities | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Ultionis Casses | 52-71 | Malum Umbra | CHA0353 | 2008 | Chaosium | Call of Cthulhu (Invictus)
| |
| The Ultra-Violet | Artifact (R) | Limited | CAO1300-1 | 1996 | Chaosium | Mythos
| |
| Ultravox | | Hastur Hobbies | | n/a | Self Published | Mythos
| |
| Ululatus Anima | Oct 2014 | shoggoth.net | | n/a | Self Published | Call of Cthulhu (Classic)
| |
| Umr at-Tawil | Character (F) | Seekers of Knowledge | CT59 | 2012 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| UNACKNOWLEDGED | 2018 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
| |
| Unacknowledged Author/Enthusiastic Chorus Girl | Investigator (F) | Dreamlands | CAO1307-1 | 1997 | Chaosium | Mythos
| |
| Unausprechlichen Kulten | Tome (C) | Limited | CAO1300-1 | 1996 | Chaosium | Mythos
| |
| Unausspechlichen Klutzen | 1-12 | Unausspechlichen Klutzen | | 2011 | Bully Pulpit Games | Fiasco Classic
| |
| Unaussprechlichen Klutzen | 21-27 | The Unspeakable Oath | 21 | Jul 2012 | Pagan Publishing | Fiasco
| |
| Unaussprechlichen Kulten | Support (F) | The Sleeper Below | CT63 | 2014 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unaussprechlichen Kulten, Von Junzt's Dark Masterpiece | Support (R) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unavoidable Delay | Event (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unbearable Likeness | | The Unbearable Likeness | FXC-01 | Jun 2019 | Stygian Fox | Call of Cthulhu (Now)
| |
| Unbearable Visions | Support (C) | Eldritch Edition | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unborn | 2007 | talesofterror.net | | n/a | Self Published | Call of Cthulhu (Classic)
| |
| Unbound! | Event (F) | The Order of the Silver Twilight | CT33 | 2010 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unboxing | | Unboxing | | Aug 2021 | Chaosium | Call of Cthulhu (Classic)
| |
| An Unbreakable Oath | Support (R) | Eldritch Edition | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Uncle Dave's Cabin | Location (F) | Scooby Doo Set 2 | | Mar 1999 | Self Published | Mythos
| |
| Uncle George's Halloween Party | | Serendipity's Circle | 12 | n/a | Self Published | Call of Cthulhu (Classic)
| |
| Uncle George's Murder Mystery Party | | Serendipity's Circle | 18 | n/a | Self Published | Call of Cthulhu (Classic)
| |
| Uncle Nathaniel Rogers | Ally (F) | Scooby Doo Set 2 | | Mar 1999 | Self Published | Mythos
| |
| Uncle Nathaniel's Place | Location (F) | Scooby Doo Set 2 | | Mar 1999 | Self Published | Mythos
| |
| Uncle Timothy's Will | 6-15 | Blood Brothers | CHA2329 | 1990 | Chaosium | Call of Cthulhu (Classic)
| |
| The Unclean | 2015 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
| |
| The Unclean | 149-172 | World War Cthulhu: Cold War - Covert Actions | CB71972 | 2017 | Cubicle 7 | Call of Cthulhu (Cold War)
| |
| Unconventional Firearms | 62-66 | The Unspeakable Oath | 23 | Aug 2013 | Pagan Publishing | Call of Cthulhu (Classic)
| |
| Unconventional Weapons | 108-112 | Terrors of the Secret War | MUH050025AC | 2014 | Modiphius Entertainment | Call of Cthulhu (Achtung!)
| |
| Undead in Reality | 27-39 |  RPG Review | 28.29 | Sep 2015 | Self Published | None
| |
| Undead Wizard | | Undead Wizard | | 2015 | Pleasant Company Games | Ancient Terrible Things
| |
| Under a Blood Red Sky | 1997 | talesofterror.net | | n/a | Self Published | Call of Cthulhu (Classic)
| |
| Under a Blood Red Sky: A Tale of Terror | | Chaosium Digest | v21n05 | Sep 1997 | Chaosium | Call of Cthulhu (Dreamlands)
| |
| Under a Grey Sun | 1-3 | Under a Grey Sun | | 2016 | Self Published | Lovecraftesque
| |
| Under a Werewolf Moon | 148-159 |  Shadows Over Filmland | PELGT06 | 2008 | Pelgrane Press | Trail of Cthulhu
| |
| Under a Winter's Snow | | Under a Winter's Snow | FXC-09 | 2020 | Stygian Fox | Call of Cthulhu (Classic)
| |
| Under Cover of Darkness | Support (F) | Denizens of the Underworld | CT62 | 2014 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Under Dark Waves | | Under Dark Waves | AHB05 | 2020 | Fantasy Flight Games | Arkham Horror
| |
| Under New Management | 2017 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
| |
| Under New Management | 1998 | talesofterror.net | | n/a | Self Published | Call of Cthulhu (Classic)
| |
| Under Surveillance | Support (F) | For the Greater Good | CT64 | 2015 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Under the Big Top | | More Tales of Terror | PAG2105 | 2000 | Pagan Publishing | Call of Cthulhu (Classic)
| |
| Under the Boardwalk | 7-34 | Farewell, My Sanity | CHA0346 | 2007 | Chaosium | Call of Cthulhu (Classic)
| |
| Under the Charcoal Sky | 140-143 | APOCTHULHU | cr6100 | 2020 | Cthulhu Reborn | d100 (APOCTHULHU)
| |
| Under the Cloak of Darkness | Support (R) | Unspeakable Tales | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Under the Frozen Grove | | Under the Frozen Grove | | Jun 2021 | Chaosium | Call of Cthulhu (Classic)
| |
| Under the Mask | 117-119 | Lovecraftesque | | 2016 | Black Armada | Lovecraftesque
| |
| Under the Microscope | Event (F) | The Spoken Covenant | CT36 | 2010 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Under the Porch | Support (F) | The Horror Beneath the Surface | CT20 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Under the Pyramids | | Under the Pyramids | EH05 | 2015 | Fantasy Flight Games | Eldritch Horror
| |
| Under the Tree | | Under the Tree | | Mar 2021 | Chaosium | Call of Cthulhu (Now)
| |
| Under the Yellow Sign | Support (F) | For the Greater Good | CT64 | 2015 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Undercover Agent | Character (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Undercover Security | Character (F) | Call of Cthulhu The Card Game | CT18 | 2008 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Undercover Security | Character (C) | Eldritch Edition | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Underground | 25-26, 35-36 | The Good Games Guide | 1 | Win 1985 | Games Workshop | Call of Cthulhu (WWII)
| |
| The Underground | 119-139 | H.P. Lovecraft's Dunwich | CHA8802 | 2002 | Chaosium | Call of Cthulhu (Classic)
| |
| The Underground | 97-117 | Return to Dunwich | CHA2330 | 1991 | Chaosium | Call of Cthulhu (Classic)
| |
| Underground Asylum | Support (F) | The Spawn of the Sleeper | CT19 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| The Underground Conspiracy | Conspiracy (F) | Conspiracies of Chaos | | 2006 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Underground Conspiracy | Conspiracy (F) | Conspiracies of Chaos | CT14e | 2011 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Underground Menace | 18-21 | Different Worlds | 19 | Feb 1982 | Chaosium | Call of Cthulhu (Classic)
| |
| The Underground Menace | A-D | Fragments of Fear | CHA2310 | 1985 | Chaosium | Call of Cthulhu (Classic)
| |
| Underground Press | Support (R) | Eldritch Edition | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Underground River | Support (U) | Eldritch Edition | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Underground Seattle | Location (F) | Seattle | | n/a | Self Published | Mythos
| |
| Underneath the Surface | Event (F) | The Twilight Beckons | CT40 | 2011 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Undersea Treasures | Support (R) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Undertow | 13-17 | Fear's Sharp Little Needles | 3005 | 2018 | Stygian Fox | Call of Cthulhu (Now)
| |
| Undertow of Madness | | Undertow of Madness | | 2020 | Grimlord Games | The Everrain
| |
| The Underwater Conspiracy | Conspiracy (F) | The Spawn of the Sleeper | CT19 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| The Underworld | 72-104 | The Sense of the Sleight of Hand Man | APU8001 | 2013 | Arc Dream Publishing | Call of Cthulhu (Dreamlands)
| |
| Underworld Contacts | Event (F) | Eldritch Edition Premium Starter Set | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Underworld Contacts | Event (C) | Unspeakable Tales | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Underworld Monsters Deck | | Thastygliax's Vault | | n/a | Self Published | Mythos
| |
| Undimensioned and Unseen | | Undimensioned and Unseen | AHC06 | 2017 | Fantasy Flight Games | Arkham Horror: The Card Game
| |
| Undocumented Expedition | Event (U) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Undying Leaders | 3-15 | Undying Leaders | CHA0343 | 2007 | Chaosium | Call of Cthulhu (Classic)
| |
| The Undying Leaders of Tibet | 35-77 | Undying Leaders | CHA0343 | 2007 | Chaosium | Call of Cthulhu (Classic)
| |
| Une Nuit a l'Opera | 2019 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
| |
| Unearthing the Ancients | Event (U) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unearthing the Ancients | Event (F) | Call of Cthulhu The Card Game | CT18 | 2008 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Uneasy Translator | Character (F) | The Cacophony | CT39 | 2010 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unending Festivities | Conspiracy (F) | Terror in Venice | CT61 | 2013 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unexpected Ally | Character (R) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
 Unexpected Bonus | 84-85 | Unveiled Threats | WDF23600 | 2011 | WildFire Games | Framewerk (CthulhuTech)
| |
| An Unexpected Calamity | | Chaosium Digest | v18n05 | Feb 1997 | Chaosium | Mythos
| |
| An Unexpected Calamity | Event (U) | Limited | CAO1300-1 | 1996 | Chaosium | Mythos
| |
| An Unexpected Calamity | Event (R) | New Aeon | CAO1311-1 | 1997 | Chaosium | Mythos
| |
| Unexpected Eclipse | Event (C) | New Aeon | CAO1311-1 | 1997 | Chaosium | Mythos
| |
| Unexpected Guest | Aug 2009 | talesofterror.net | | n/a | Self Published | Call of Cthulhu (Classic)
| |
| An Unexpected Return | 20-78 | Once Men | CHA0356 | 2008 | Chaosium | Call of Cthulhu (Once Men)
| |
| Unexpected Surprise | Event (F) | Scooby Doo Set 2 | | Mar 1999 | Self Published | Mythos
| |
| Unfathomable Elder Thing | Character (F) | The Horror Beneath the Surface | CT20 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unforseen Setback | Support (F) | Shadow of the Monolith | CT52 | 2012 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| The Unfortunate Cat Klaus, Forsaken Feline | Character (P) | Eldritch Edition Promo | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unfortunate Eskimo | Adventure (F) | Rosemary's Baby | | n/a | Self Published | Mythos
| |
| The Unfortunate Nephew/Controversial French Mystic | Investigator (F) | Limited | CAO1300-1 | 1996 | Chaosium | Mythos
| |
| Unfriendly * | 2009 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
| |
| Unhealthy Curiosity | Event (C) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unhealthy Fixation | Support (F) | The Gleaming Spiral | CT44 | 2011 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unhealthy Occupation | 62-75 | The Unspeakable Oath | 14/15 | 1997 | Pagan Publishing | Call of Cthulhu (Classic)
| |
| Unhinged Laborer | Character (F) | The Mark of Madness | CT66 | 2015 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| The Unholies | 49-50 | The Black Seal | 2 | Mar 2003 | Brichester University Press | Call of Cthulhu (Now)
| |
| Unholy Presents | | Unholy Presents | | 2016 | Atlas Games | Lost in R'lyeh
| |
| Unicum: H P Lovecraft Edition | | Unicum: H P Lovecraft Edition | | 2014 | Sphinx Speileverlag | Unicum
| |
| Unimaginable Apparition | Monster (F) | Rosemary's Baby | | n/a | Self Published | Mythos
| |
| Union and Disillusion | | Union and Disillusion | AHC33 | 2019 | Fantasy Flight Games | Arkham Horror: The Card Game
| |
| Unique High Priests | | Unique High Priests | | 2016 | Petersen Games | Cthulhu Wars
| |
| Unit 23 | 2009 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
| |
| The United Colonial Coalition Asteroid Colonies for the End Time Setting | 74-78 | Ripples From Carcosa | CHA0312 | 2005 | Chaosium | Call of Cthulhu (End Time)
| |
| United Nations | Location (C) | New Aeon | CAO1311-1 | 1997 | Chaosium | Mythos
| |
| Units of Dust | 23-33 | Secrets of the Dust | MUH050028 | 2016 | Modiphius Entertainment | Call of Cthulhu (Achtung!)
, Savage Worlds (Achtung!)
, Savage Worlds (Dust)
| |
| University of Tokyo | 334-342 | Secrets of Japan | CHA2392 | 2005 | Chaosium | Call of Cthulhu (Classic)
| |
| Unknown Kadath | Support (F) | Journey to Unknown Kadath | CT31 | 2010 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unland | 102-107 | Fear's Sharp Little Needles | 3005 | 2018 | Stygian Fox | Call of Cthulhu (Now)
| |
| Unlicensed Garage | Support (R) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unlikely Informant | Character (F) | That Which Consumes | CT45 | 2011 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unlocking Dice: Dice Vermiis Mysteriis | | Unlocking Dice: Dice Vermiis Mysteriis | | 2020 | Petersen Games | Unlocking Insanity
| |
| Unmasked Rally | 1-16 | Unmasked Rally | | 2016 | Xipe Totec Press | None
| |
| The Unmasking | 1-8 | The Unmasking | | 2013 | Self Published | Call of Cthulhu (Delta Green)
| |
| Unmasking Corruption | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unmasking Cowardice | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unmasking Cruelty | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unmasking Hubris | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unmasking Idiocy | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unmasking Shame | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unmasking Treachery | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unmoving Finger | Support (C) | Forgotten Cities | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unnamable | Oct 2005 | shoggoth.net | | n/a | Self Published | Call of Cthulhu (Classic)
| |
| The Unnamable House | Support (R) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unnamable House | Location (U) | Limited | CAO1300-1 | 1996 | Chaosium | Mythos
| |
| The Unnamable One | Adventure (F) | House of Tindalos | | n/a | Self Published | Mythos
| |
| Unnameable | | Unnameable | CW-U25 | 2019 | Petersen Games | Cthulhu Wars
| |
 The Unnameable Undone | 1:47 |  Horror on the Orient Express Music | AOCD7004 | 2005 | A O Music | Call of Cthulhu (Classic)
| |
| Unnamed Deck | | Hastur Hobbies | | n/a | Self Published | Mythos
| |
| Unnatural Behaviour | | Tales of Terror (II) | PAG2102 | 1996 | Pagan Publishing | Call of Cthulhu (Classic)
| |
| Unnatural Behaviour | 1996 | talesofterror.net | | n/a | Self Published | Call of Cthulhu (Classic)
| |
| Unnatural Mystic | | Unnatural Mystic | | 2018 | Pleasant Company Games | Ancient Terrible Things
| |
| Unnatural Stealth | Event (C) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unnatural Stealth | Event (F) | Arkham Edition Premium Starter Set | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unnatural Stealth | Event (F) | Arkham Edition Premium Starter Set | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unnatural Stealth | Event (F) | Arkham Edition Premium Starter Set | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unnatural Stealth | Event (F) | Arkham Edition Premium Starter Set | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unnaturally Familiar: Fiendish Friends for Immortal Sorcerers | | Chaosium Digest | v36n05 | May 2002 | Chaosium | Call of Cthulhu (Classic)
| |
| Unorthodox Psychologist | Character (F) | The Thing from the Shore | CT23 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unorthodox Tactics | Conspiracy (F) | The Thing from the Shore | CT23 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unpleasant Dreams | 145-162 | Goatswood and Less Pleasant Places | CHA2393 | 2001 | Chaosium | Call of Cthulhu (Now)
| |
| Unpleasant Dreams | | Unpleasant Dreams | AG1331 | 2012 | Atlas Games | Gloom
| |
| The Unpossessed | 7 | The Whisperer | 4 | Spr 2001 | Severn Valley Press | Call of Cthulhu (Dreamlands)
| |
| The Unquiet Earth | Story (F) | Eldritch Edition | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unquiet Earth | Story (F) | Eldritch Edition Premium Starter Set | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unquiet Spirits | 70-71 | The Masks of Nyarlathotep Companion (Limited) | 60-MONC-08 | 2016 | Sixtystone Press | Call of Cthulhu (Classic)
| |
| Unquiet Spirits | 60-61 | The Masks of Nyarlathotep Companion (Unlimited) | 60-MONC-03 (?) | 2016 | Sixtystone Press | Call of Cthulhu (Classic)
| |
| The Unraveled Nerve | Support (C) | Forgotten Cities | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unravelling | | The Unravelling | | Jul 2019 | Dark Trapezohedron Productions | Call of Cthulhu (Gaslight)
| |
| The Unreflecting Mirror | Support (C) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unremembered | | Unremembered | | Jan 2019 | Chaosium | Call of Cthulhu (Now)
| |
| Unscrupulous Acquisitionist | Character (F) | The Gleaming Spiral | CT44 | 2011 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| The Unsealed Room | 22-30 | Secrets | CHA2367 | 1997 | Chaosium | Call of Cthulhu (Now)
| |
| The Unseeing Eye | Adventure (F) | House of Tindalos | | n/a | Self Published | Mythos
| |
| Unseen Forces | | Unseen Forces | SL15 | 2013 | Fantasy Flight Games | Elder Sign
| |
| Unseen Mirror | | More Tales of Terror | PAG2105 | 2000 | Pagan Publishing | Call of Cthulhu (Classic)
| |
| An Unsettled Mind | 102-117 | Bumps in the Night | PAG1014 | 2012 | Pagan Publishing | Call of Cthulhu (Classic)
| |
| Unsettling Visions | Event (R) | Forbidden Relics | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unspeakable Acts | | hyperwerx.net | | n/a | Self Published | Call of Cthulhu (Now)
| |
| Unspeakable Artifacts | 41-43 | Vision | 3 | Oct 1992 | Self Published | Call of Cthulhu (Classic)
| |
| Unspeakable Box | | Unspeakable Box | DMD-KS01 | 2019 | CMON Limited | Cthulhu: Death May Die
| |
| Unspeakable Darkness | Event (F) | Rosemary's Baby | | n/a | Self Published | Mythos
| |
| Unspeakable Horrors | 204-221 | CthulhuTech | WDF23000 | 2007 | WildFire Games | Framewerk (CthulhuTech)
| |
| Unspeakable Letters Promo Card | | Unspeakable Letters Promo Card | | 2014 | Playroom Entertainment | Unspeakable Words
| |
| The Unspeakable Oath | Adventure (R) | Expeditions of Miskatonic University | CAO1301-1 | 1996 | Chaosium | Mythos
| |
| The Unspeakable Oath | Event (F) | Terror in Venice | CT61 | 2013 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| The Unspeakable Oath | | The Unspeakable Oath | AHC13 | 2017 | Fantasy Flight Games | Arkham Horror: The Card Game
| |
| Unspeakable Oath | Event (R) | Unspeakable Tales | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unspeakable Promise | Support (F) | The Mark of Madness | CT66 | 2015 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unspeakable Research | Event (F) | Spawn of Madness | | 2006 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unspeakable Research | Event (F) | Spawn of Madness | CT12e | 2011 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unspeakable Resurrection | Event (C) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unspeakable Resurrection | Event (F) | Arkham Edition Premium Starter Set | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unspeakable Resurrection | Event (F) | Arkham Edition Premium Starter Set | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unspeakable Resurrection | Event (F) | Call of Cthulhu The Card Game | CT18 | 2008 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| Unspeakable Revelations | Event (R) | Arkham Edition | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| Unspeakable Secrets Made Easy | 92-95 | Dragon | 150 | Oct 1989 | TSR | Call of Cthulhu (Classic)
| |
| Unspeakable Transformation | Event (F) | The Path to Y'ha-nthlei | CT24 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG
| |
| The Unspeakable Vault | | The Unspeakable Vault | SJG1455 | 2008 | Steve Jackson Games | Munchkin
| |
| Unspeakable Words | | Unspeakable Words | PLE26100 | 2007 | Playroom Entertainment | Unspeakable Words
| |
| Unspeakable Words Deluxe Edition | | Unspeakable Words Deluxe Edition | | 2015 | Playroom Entertainment | Unspeakable Words
| |
| An Unspoken Agreement | Support (R) | Eldritch Edition | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
| |
| The Unspoken Silence | Oct 2015 | shoggoth.net | | n/a | Self Published | Call of Cthulhu (Invictus)
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| Unstable Energies | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
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| Unstoppable Hound | Character (C) | Unspeakable Tales | | 2004 | Fantasy Flight Games | Call of Cthulhu CCG
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| The Unsung Saga | 13-34 | The Ravenar Sagas | CHA0348 | 2008 | Chaosium | Call of Cthulhu (Dark Ages)
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| Untimely Burial | Event (F) | Terror in Venice | CT61 | 2013 | Fantasy Flight Games | Call of Cthulhu LCG
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| Unusual Card Combinations for Mythos | | Chaosium Digest | v28n05 | Jun 1999 | Chaosium | Mythos
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| Unusual Locations | B:38-51 | Cthulhu Britannica: London Box Set | CB7354 | 2014 | Cubicle 7 | Call of Cthulhu (Classic)
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| Up Against the Wall, Suckers! | 54, 56-57 | Shadis | 19.5 | Jun 1995 | Alderac Entertainment Group | None
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| Up for Grabs | Support (U) | Masks of Nyarlathotep | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
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| Up Jumped the Reaper | 85-90 | Fear's Sharp Little Needles | 3005 | 2018 | Stygian Fox | Call of Cthulhu (Now)
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| Updated Personnel | 14-19 | God Game Black | CB71207 | 2013 | Cubicle 7 | Call of Cthulhu (Laundry)
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 Upgraded Ritual and Doom Tracks | | Upgraded Ritual and Doom Tracks | CW-U11 | 2017 | Petersen Games | Cthulhu Wars
| |
| The Upper House | | Chaosium Digest | v35n11 | Mar 2002 | Chaosium | Call of Cthulhu (Classic)
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| The Upper House | 172-191 | Tatters of the King | CHA23104 | 2006 | Chaosium | Call of Cthulhu (Classic)
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| Urban Exploration | 2020 | The Fairfield Project | | n/a | Self Published | Call of Cthulhu (Delta Green)
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| Urban Renewal | Event (U) | Forgotten Cities | | 2005 | Fantasy Flight Games | Call of Cthulhu CCG
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| Urban Trailblazer | Character (F) | Terror in Venice | CT61 | 2013 | Fantasy Flight Games | Call of Cthulhu LCG
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| The Urge to Purge | 12 | The Unspeakable Oath | 13 | Jan 1996 | Pagan Publishing | Call of Cthulhu (Now)
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| Uroborus | Character (F) | Written and Bound | CT53 | 2012 | Fantasy Flight Games | Call of Cthulhu LCG
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| Ursinus' Animal Show | 74-83 | The Gods Hate Me | CHA0402 | 2011 | Chaosium | Call of Cthulhu (Invictus)
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| Urumi | Support (F) | The Unspeakable Pages | CT57 | 2012 | Fantasy Flight Games | Call of Cthulhu LCG
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| US Archaeological Society | Character (F) | The Sleeper Below | CT63 | 2014 | Fantasy Flight Games | Call of Cthulhu LCG
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| US Handguns for Call of Cthulhu and Gaslight | 7-16 | The Unspeakable Oath | 3 | Aug 1991 | Pagan Publishing | Call of Cthulhu (Classic)
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| The US Intelligence Community in the 1970s | 9-24 | World War Cthulhu: Cold War - Our American Cousins | CB71973 | 2017 | Cubicle 7 | Call of Cthulhu (Cold War)
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| Using Children as Investigators | | Chaosium Digest | v03n06 | Aug 1993 | Chaosium | Call of Cthulhu (Classic)
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| Using Cthulhu Mythos Knowledge | | Chaosium Digest | v31n09 | Jun 2000 | Chaosium | Call of Cthulhu (Classic)
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| Using Customized Newspaper Articles | 32-35 | The Masks of Nyarlathotep Companion (Limited) | 60-MONC-08 | 2016 | Sixtystone Press | Call of Cthulhu (Classic)
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| Using Customized Newspaper Articles | 29-31 | The Masks of Nyarlathotep Companion (Unlimited) | 60-MONC-03 (?) | 2016 | Sixtystone Press | Call of Cthulhu (Classic)
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| Using Dreams in RPGs | 46-47 | Serendipity's Circle | 8 | Sum 1996 | Self Published | None
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| Using Folk Magic in Call of Cthulhu Games | 22-27 | Cthulhu Britannica: Folklore | CB7351 | 2012 | Cubicle 7 | Call of Cthulhu (Classic)
| |
| Using Folklore in Call of Cthulhu Games | 14-20 | Cthulhu Britannica: Folklore | CB7351 | 2012 | Cubicle 7 | Call of Cthulhu (Classic)
| |
| Using Jackson Elias | 62-66 | The Masks of Nyarlathotep Companion (Limited) | 60-MONC-08 | 2016 | Sixtystone Press | Call of Cthulhu (Classic)
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| Using Jackson Elias | 54-57 | The Masks of Nyarlathotep Companion (Unlimited) | 60-MONC-03 (?) | 2016 | Sixtystone Press | Call of Cthulhu (Classic)
| |
| Using Music | 28-29 | Cryptych | 8 | Oct 1994 | ILM International | Call of Cthulhu (Classic)
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| Using Qi | 9-? | The Dark Times | 2 | Jan 2018 | Self Published | Call of Cthulhu (Classic)
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| Using Thermal Imagers in RPGs | 41-46 | Protodimension | 8 | Spr 2011 | Kinstaff Media | Call of Cthulhu (Now)
, Dark Conspiracy
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| The Usual Suspects | Conspiracy (F) | For the Greater Good | CT64 | 2015 | Fantasy Flight Games | Call of Cthulhu LCG
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| USX Modern Day Heroes: Cthulhu Monsters | | USX Modern Day Heroes: Cthulhu Monsters | | 2008 | RAFM | USX Modern Day Heroes
| |
| Utilities | 53-73 | Cthulhu Dark Ages | CHA2398 | 2004 | Chaosium | Call of Cthulhu (Dark Ages)
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