| Title | Code | Date | Publisher | System (Setting) |
|---|
 S-P-O-N-G-E: Fight the Evil | | 2001 | Self Published | S-P-O-N-G-E: Fight the Evil |
 S. Petersen's Field Guide to Creatures of the Dreamlands | CHA5107 | 1989 | Chaosium | Call of Cthulhu (Dreamlands) |
| S. Petersen's Field Guide to Cthulhu Monsters | CHA5105 | 1988 | Chaosium | Call of Cthulhu (Classic) |
| S. Petersen's Field Guide to Lovcraftian Horrors | CHA23138 | 2015 | Chaosium | Call of Cthulhu (Classic) |
| Sacraments of Evil | CHA2345 | 1993 | Chaosium | Call of Cthulhu (Gaslight) |
| Sacraments of Evil Fix-It-Up-Kit | | 1994 | Arteface | [None Listed] |
| Sacrificial Fire Mini Expansion | | 2019 | Renegade Game Studios | Gates of Delerium |
 Safe Space | | Nov 2022 | Chaosium | Call of Cthulhu (Now) |
| Saigon: 1968 | PELGDG03D | 2021 | Pelgrane Press | Trail of Cthulhu |
| Saint's Peak | | Dec 2023 | Chaosium | Call of Cthulhu (Classic) |
| Salo's Glory | FXC-11 | 2020 | Stygian Fox | Call of Cthulhu (Strange Aeons) [Future] |
| The Saltwater Inheritance | | Jun 2019 | Chaosium | Call of Cthulhu (Classic) |
| Salvation at the Devil's Courthouse | | Oct 2021 | Chaosium | Call of Cthulhu (Classic) |
 Samhain | 2 | Spr 1987 | Self Published | None |
| Samurai - Weapons of Feudal Japan | | Mar 2018 | Chaosium | Call of Cthulhu (Strange Aeons) [Sengoku Period] |
| Samurai Firearms and Bestiary | | Jun 2018 | Chaosium | Call of Cthulhu (Strange Aeons) [Sengoku Period] |
| Samurai: A Monograph | | Mar 2018 | Chaosium | Call of Cthulhu (Strange Aeons) [Sengoku Period] |
| Sanctum of Twilight | MAD26 | 2018 | Fantasy Flight Games | Mansions of Madness |
| Sanctum Secorum | 10 | Oct 2016 | Sanctum Media | Dungeon Crawl Classics |
| Sanctum Secorum | 18 | Nov 2016 | Sanctum Media | Dungeon Crawl Classics |
| Sanctum Secorum | 8 | Jan 2016 | Sanctum Media | Dungeon Crawl Classics |
| Sanctum Secorum | 9 | Feb 2016 | Sanctum Media | Dungeon Crawl Classics |
| Sanctum Secorum | 33 | Mar 2018 | Sanctum Media | Dungeon Crawl Classics |
| Sanctum Secorum | 36b | Jun 2018 | Sanctum Media | Dungeon Crawl Classics |
| Sanctum Secorum | 39b | Oct 2018 | Sanctum Media | Dungeon Crawl Classics |
 Sandy Petersen's Cthulhu Mythos | | 2016 | Petersen Games | Pathfinder |
| Sandy Petersen's Cthulhu Mythos | | 2019 | Petersen Games | Dungeons and Dragons |
| Sanitarium Forms | CHA23135-Sanitarium | 2016 | Chaosium | Call of Cthulhu (Classic) |
| Sanity and Sorcery | | 2018 | Self Published | Lasers and Feelings (Sanity and Sorcery) |
| Sanity Check | | 2019 | Steve Jackson Games | Munchkin |
| Sanity Check Promo Card | | Feb 2020 | Steve Jackson Games | Munchkin |
| Sanity Flowchart | | Dec 2023 | Chaosium | Call of Cthulhu (Classic) |
| Sanity Tracker | | May 2019 | Chaosium | Call of Cthulhu (Classic) |
| Santa | | Dec 2019 | Chaosium | Call of Cthulhu (Now) |
| The Sassoon Files | 2 | 2019 | Sons of the Singularity | Call of Cthulhu (Classic), Cthulhu Confidential |
| The Sassoon Files: The Brother of Jesus | 3 | 2019 | Sons of the Singularity | Cthulhu Confidential, Call of Cthulhu (Classic) |
| Saturday the 14th | | Aug 2022 | Chaosium | Call of Cthulhu (Now) |
| Sauron Strikes Back | 1 | 1987 | Self Published | Call of Cthulhu (Classic) |
| Savage League of Seekers | | 2019 | Feral Games | Savage Worlds |
| Save Innsmouth | | 2016 | Just Crunch Games | The Cthulhu Hack |
| Save Our Souls | | 1989 | Self Published | Call of Cthulhu (Now) |
| The Scales of the Serpent | | Apr 2020 | Chaosium | Call of Cthulhu (Now) |
| The Scales of Time | | Dec 2017 | Chaosium | Call of Cthulhu (Classic) |
| The Scarecrow | | 1991 | Self Published | Call of Cthulhu (Now) |
| The Scarecrow * | | May 2018 | Chaosium | Call of Cthulhu (Classic) |
| Scarlett Hayes * | | 2019 | CMON Limited | Cthulhu: Death May Die |
| Scenario Upgrade Pack: In the Shadows | cr1001 | 2015 | Cthulhu Reborn | Call of Cthulhu (Classic) |
| Scenario Upgrade Pack: The Stars Are Right! | cr1002 | 2017 | Cthulhu Reborn | Call of Cthulhu (Now) |
| Scene Cards | | 2010 | Stardust Publications | Dark Aeons |
| Scene Cards 2 | | 2011 | Stardust Publications | Dark Aeons |
| The Schoolmarm's Ghost | | Apr 2024 | Chaosium | Call of Cthulhu (Classic) |
| Science Fiction Double Feature | | 2011 | Gratis Games | Call of Cthulhu (Now) |
 Scooby Doo Adventures | | | Self Published | Mythos |
| Scooby Doo Bonus Cards | | | Self Published | Mythos |
| Scooby Doo Set 1 | | | Self Published | Mythos |
| Scooby Doo Set 2 | | Mar 1999 | Self Published | Mythos |
| Scooby Doo Set 3 | | | Self Published | Mythos |
 The Scream Factory | 12 | Aut 1993 | Deadline Press | None |
| The Scream of the Mandrake | | Jun 2021 | Type40 | Call of Cthulhu (Classic) |
| The Screaming Horror of Creech Hill | | 2006 | Self Published | Call of Cthulhu (Classic) |
| Screams from Within | CT38 | 2010 | Fantasy Flight Games | Call of Cthulhu LCG |
| Scritch Scratch * | CHA23157 | 2018 | Chaosium | Call of Cthulhu (Now) |
| Sea Food | | 1996 | Self Published | Call of Cthulhu (Now) |
| The Seals of Cthulhu | | 2020 | Thing 12 Games | The Seals of Cthulhu |
| Seams of Peril | cr3005g | 2017 | Cthulhu Reborn | Call of Cthulhu (Convicts) |
| The Search for Kadath * | AHC39 | 2019 | Fantasy Flight Games | Arkham Horror: The Card Game |
| The Search for the Forbidden Door | | Nov 2022 | Chaosium | Call of Cthulhu (Classic) |
| Search for the Silver Key | CT29 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG |
| Searchers of the Unknown | | 2012 | RetroRoleplaying | Searchers of the Unknown |
| Season 2 Expansion | DMD002 | 2019 | CMON Limited | Cthulhu: Death May Die |
| Season 4 Expansion | | 2023 | CMON Limited | Cthulhu: Death May Die |
| A Season in Carcosa * | MRP0021 | 2012 | Miskatonic River Press | None |
| Season of Growth | | Dec 2023 | Chaosium | Call of Cthulhu (Now) |
| Season of the Witch | MAD02 | 2011 | Fantasy Flight Games | Mansions of Madness |
| Seattle | | | Self Published | Mythos |
| The Second Amphora | | Dec 2019 | Entente Cthuiana | Call of Cthulhu (Now) |
| Second Coming | cr5208 | Nov 2023 | Cthulhu Reborn | Cthulhu Eternal |
| Secret Cthulhu | | 2019 | Self Published | Secret Cthulhu |
| The Secret Glory | | 2021 | Self Published | Call of Cthulhu (Classic) |
| The Secret Name * | AHC30 | 2019 | Fantasy Flight Games | Arkham Horror: The Card Game |
| The Secret of Cykranosh | | 2016 | Self Published | Dungeons and Dragons |
| The Secret of Silcestre | | May 2021 | Chaosium | Call of Cthulhu (Dark Ages) |
| The Secret of the Dead Man's Satchel | SG-MT2 | 2012 | Spectrum Games | Macabre Tales |
| Secret Santa | | Nov 2021 | Chaosium | Call of Cthulhu (Classic) |
| Secret Soldiers | | 2017 | Skortched Urf' Studios | d20 |
| The Secret Song of Lake Billings | | Nov 2023 | Chaosium | Call of Cthulhu (Now) |
| The Secret War * | | 2016 | Modiphius Entertainment | The Secret War |
| Secret War Documents | MPS01044G | 2014 | Modiphius Entertainment | [None Listed] |
| Secret War Operations | | | Modiphius Entertainment | Savage Worlds (Achtung!) |
| Secrets | CHA2367 | 1997 | Chaosium | Call of Cthulhu (Now) |
| Secrets of Arkham | CT32 | 2010 | Fantasy Flight Games | Call of Cthulhu LCG |
| Secrets of Japan | CHA2392 | 2005 | Chaosium | Call of Cthulhu (Now) |
| Secrets of Kenya | CHA23109 | 2007 | Chaosium | Call of Cthulhu (Classic) |
| Secrets of Los Angeles | CHA23111 | 2007 | Chaosium | Call of Cthulhu (Classic) |
| Secrets of Morocco | CHA23105 | 2008 | Chaosium | Call of Cthulhu (Classic) |
| Secrets of New Orleans * | CHA23114 | 2009 | Chaosium | Call of Cthulhu (Classic) |
| Secrets of New York | CHA23103 | 2005 | Chaosium | Call of Cthulhu (Classic) |
| Secrets of Salem: The Milk of Shub-Niggurath | 7 | 2020 | The Ghoul's Notes | Trail of Cthulhu |
| Secrets of San Francisco | CHA23108 | 2006 | Chaosium | Call of Cthulhu (Classic) |
| Secrets of the Congo | CHA0387 | 2010 | Chaosium | Call of Cthulhu (Classic) |
| Secrets of the Dust | MUH050028 | 2016 | Modiphius Entertainment | Savage Worlds (Dust), Call of Cthulhu (Achtung!), Savage Worlds (Achtung!) |
| Secrets of the Glen | | May 2022 | Chaosium | Call of Cthulhu (Now) |
| Secrets of the Lost Tomb | | 2015 | Everything Epic Games | Secrets of the Lost Tomb |
| Secrets of the Order | | 2021 | Fantasy Flight Games | Arkham Horror |
| Secrets of the Void | WDF33110 | 2014 | WildFire Games | The Void |
| Secrets of Tibet | CHA23129 | 2013 | Chaosium | Call of Cthulhu (Classic) |
| See No Evil, Speak No Evil | | Sep 2024 | Chaosium | Call of Cthulhu (Now) |
| Seeds of Evil | | 2016 | Wayward Rogues Publishing | Pathfinder |
| Seekers of Knowledge | CT59 | 2012 | Fantasy Flight Games | Call of Cthulhu LCG |
| Seized by Sugar | | Oct 2024 | Chaosium | Call of Cthulhu (Now) |
| Seizure | | 2005 | Self Published | Call of Cthulhu (Strange Aeons) [1962] |
| Sell Yourself | | Apr 2024 | Chaosium | Call of Cthulhu (Now) |
| The Sense of the Sleight of Hand Man * | | 2010 | Self Published | Call of Cthulhu (Dreamlands) |
| The Sense of the Sleight of Hand Man | APU8001 | 2013 | Arc Dream Publishing | Call of Cthulhu (Dreamlands) |
| Sensitive Cases Division | | Aug 2023 | Chaosium | Call of Cthulhu (Now), Call of Cthulhu (Classic) |
| Sepulchral Shoggoths | | Aug 2021 | Last Mile Game Logistics | Call of Cthulhu (Classic) |
| The Seraph Chronicles 4: Before the Flood * | | | Modiphius Entertainment | Call of Cthulhu (Classic) |
| The Seraphim Club | | Nov 2023 | Chaosium | Call of Cthulhu (Classic) |
 Serena's Dojo | | 1999 | Self Published | Mythos |
| Serendipity's Circle | 10 | | Self Published | [None Listed] |
| Serendipity's Circle | 11 | | Self Published | Call of Cthulhu (Now) |
| Serendipity's Circle | 12 | | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 15 | | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 16 | | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 17 | | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 18 | | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 19 | | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 20 | | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 9 | | Self Published | [None Listed] |
| Serendipity's Circle | 1 | Jan 1995 | Self Published | Dark Conspiracy, Call of Cthulhu (Classic), Call of Cthulhu (Now), None |
| Serendipity's Circle | 2 | Mar 1995 | Self Published | Call of Cthulhu (Classic), The Whispering Vault, Bloodshadows, Dark Conspiracy |
| Serendipity's Circle | 3 | May 1995 | Self Published | None, Chill, Bloodshadows, Call of Cthulhu (Classic) |
| Serendipity's Circle | 4 | Jul 1995 | Self Published | Shattered Dreams, Mage: The Ascension, Chill, The Whispering Vault, Pandemonium, Bloodshadows, Call of Cthulhu (Classic) |
| Serendipity's Circle | 5 | Sep 1995 | Self Published | Dark Conspiracy, Call of Cthulhu (Now), The Whispering Vault, Don't Look Back, Chill, None, Over the Edge |
| Serendipity's Circle | 6 | Win 1995 | Self Published | Bureau 13, Nephilim, Call of Cthulhu (Now), Call of Cthulhu (Classic), The Whispering Vault, Immortal: The Invisible War |
| Serendipity's Circle | S1 | 1995 | Self Published | Call of Cthulhu (Now), None, Dark Conspiracy, Call of Cthulhu (Classic) |
| Serendipity's Circle | 7 | Mar 1996 | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 8 | Sum 1996 | Self Published | Lost Souls, Call of Cthulhu (Now), The Whispering Vault, Don't Look Back, Nephilim, Chill, None, Call of Cthulhu (Classic), Shattered Dreams, Bloodshadows |
| Serendipity's Circle | S2 | 1996 | Self Published | The Whispering Vault, Don't Look Back, Call of Cthulhu (Now), Call of Cthulhu (Classic), Shattered Dreams, Bloodshadows, None |
| Serendipity's Circle | 13 | Win 1997 | Self Published | Call of Cthulhu (Classic) |
| Serendipity's Circle | 14 | Spr 1998 | Self Published | Call of Cthulhu (Classic) |
| Sermon of Sludge | | Aug 2021 | Chaosium | Call of Cthulhu (Strange Aeons) [1973] |
| The Serpent and the Sands | MUH0010330 | 2023 | Modiphius Entertainment | Achtung! Cthulhu |
| Sesqua Valley | | | Self Published | Mythos |
| A Settling of Snow | | Sep 2023 | The Black Fortress | A Settling of Snow |
| Seven Blasphemous Books | | 2014 | Long Winter Publishing | None |
| Seven Sister Hills | | Jul 2021 | Chaosium | Call of Cthulhu (Now) |
| The Sevenfold Path | CHA0403 | 2011 | Chaosium | Call of Cthulhu (Classic) |
| The Seventh Circle | PELG014 | 2014 | Pelgrane Press | Call of Cthulhu (Classic) |
| Seventh-Inning Slaughter! | MUH052304 | 2021 | Modiphius Entertainment | Achtung! Cthulhu |
| Shade of Yog-Sothoth | | Nov 2019 | Chaosium | Call of Cthulhu (Classic) |
| Shades of Terror | | 2002 | Pinnacle Entertainment Group | Savage Worlds |
| Shadis | 10 | Nov 1993 | Alderac Entertainment Group | None |
| Shadis | 13 | May 1994 | Alderac Entertainment Group | None |
| Shadis | 15 | Sep 1994 | Alderac Entertainment Group | None |
| Shadis | 17 | Jan 1995 | Alderac Entertainment Group | None |
| Shadis | 18 | Mar 1995 | Alderac Entertainment Group | None |
| Shadis | 19.5 | Jun 1995 | Alderac Entertainment Group | Plotwerks, None, Call of Cthulhu (Classic), Man-O-War |
| Shadis | 20.5 | Aug 1995 | Alderac Entertainment Group | None |
| Shadis | 22 | Dec 1995 | Alderac Entertainment Group | None |
| Shadis | 25 | Mar 1996 | Alderac Entertainment Group | None |
| Shadis | 26 | Apr 1996 | Alderac Entertainment Group | Call of Cthulhu (Now), None |
| Shadis | 27 | May 1996 | Alderac Entertainment Group | Call of Cthulhu (Now) |
| Shadis | 38 | Jul 1996 | Alderac Entertainment Group | Call of Cthulhu (Classic) |
| Shadis | 41 | Oct 1997 | Alderac Entertainment Group | Call of Cthulhu (Classic) |
| Shadis | 52 | Oct 1998 | Alderac Entertainment Group | Call of Cthulhu (Classic) |
| Shadow and Illusion | | Apr 2024 | Chaosium | Call of Cthulhu (Now) |
| Shadow Hunters | | 2017 | Devil Pig Games | Shadows Over Normandie |
| The Shadow in the Tree * | | 2003 | Self Published | Call of Cthulhu (Classic) |
| Shadow Kingdoms | | 2006 | Self Published | Call of Cthulhu (Dark Ages) |
| The Shadow of a Dark God | | 2001 | Warp Spawn Games | The Shadow of a Dark God |
| The Shadow of Krampus | | 2012 | Spectrum Games | Macabre Tales |
| Shadow of Miskatonic | | 2020 | Self Published | Shadow of Miskatonic |
| Shadow of the Crawling Chaos | MUH0010337 | Aug 2024 | Modiphius Entertainment | Achtung! Cthulhu |
| Shadow of the Elder Gods | LGL300 | 2015 | Laboratory Games | Shadow of the Elder Gods |
| Shadow of the Irminsul | | Jun 2023 | Twin Engine Publishing | Cthulhu Eternal |
| Shadow of the Monolith | CT52 | 2012 | Fantasy Flight Games | Call of Cthulhu LCG |
| Shadow on the Sea | | Nov 2020 | Chaosium | Call of Cthulhu (Classic) |
| The Shadow Over Dunsmore Point | | 2019 | Self Published | Dungeons and Dragons |
| The Shadow Over Innsmouth * | | 2019 | Ediciones Idea | Choose Cthulhu |
| The Shadow Over Innsmouth | | Feb 2023 | Steve Jackson Games | Choose Cthulhu |
| The Shadow Over Kingsport | | 2021 | Steampop Games | Whispers in the Dark |
| The Shadow Over Providence | CHA23163 | 2019 | Chaosium | Call of Cthulhu (Classic) |
| The Shadow Over Providence | CHA23183 | Sep 2023 | Chaosium | Call of Cthulhu (Classic) |
| The Shadow Over the Sierra Madre | | Oct 2024 | Chaosium | Call of Cthulhu (Darker Trails) |
| The Shadow Over Washington | PELGOC07D | 2018 | Pelgrane Press | Cthulhu Confidential |
| Shadow Under Devil's Reef | GMG53017 | 2017 | Goodman Games | Dungeon Crawl Classics |
| Shadow War | | | WildFire Games | CthulhuTech |
| Shadowfall | BB-WBC-005 | 2019 | Baggage Books | Cepheus Engine |
| Shadows of an Inner Darkness * | GGP | 2019 | Golden Goblin Press | None |
| Shadows of Atlantis | MUH01022CS | 2015 | Modiphius Entertainment | Call of Cthulhu (Achtung!), Savage Worlds (Achtung!) |
| Shadows of Atlantis | MUH051747 | 2022 | Modiphius Entertainment | Achtung! Cthulhu |
| Shadows of Cthulhu | MGP6132 | 2008 | Reality Deviant | True 20 |
| Shadows of the Old Subway | | Dec 2023 | Self Published | Call of Cthulhu (Classic), GURPS (Horror) |
| Shadows of the Quartinex | | 2009 | Self Published | Yellow Dawn |
| Shadows of the Quartinex * | | 2013 | Self Published | Yellow Dawn |
| Shadows of War | CHA0349 | 2008 | Chaosium | Call of Cthulhu (WWII) |
| Shadows of Yith | | Jun 2024 | Chaosium | Call of Cthulhu (Now) |
| Shadows of Yog-Sothoth * | CHA2010 | 1982 | Chaosium | Call of Cthulhu (Classic) |
| Shadows of Yog-Sothoth * | CHA2397 | 2004 | Chaosium | Call of Cthulhu (Classic) |
| Shadows Over Filmland | PELGT06 | 2008 | Pelgrane Press | Trail of Cthulhu |
| Shadows Over Normandie | 58303 | 2015 | Devil Pig Games | Shadows Over Normandie |
| Shadows Over Scotland | CB7353 | 2011 | Cubicle 7 | Call of Cthulhu (Classic) |
| Shadows Over Stillwater | CHA23156 | 2019 | Chaosium | Call of Cthulhu (Darker Trails) |
| Shadyvill | | 2006 | Self Published | Call of Cthulhu (Now) |
| The Shaft | | 2007 | Self Published | The World of Darkness |
| Shaggai Map | CW-M11 | 2019 | Petersen Games | Cthulhu Wars |
| The Shambler Between Worlds | | Dec 2022 | Chaosium | Call of Cthulhu (Classic) |
| Shantak and Y'golonac * | | 2002 | Wizards of the Coast | Call of Cthulhu (Classic) |
| Shape Shifting Horrors | | Apr 2022 | Chaosium | Call of Cthulhu (Classic) |
| Shattered Aeons * | AHC25 | 2018 | Fantasy Flight Games | Arkham Horror: The Card Game |
| She Who Rules the Sea | WitDBS1 | 2020 | Saturday Morning Scenarios | Whispers in the Dark |
| Shenandoah | CHA0377 | 2009 | Chaosium | Call of Cthulhu (Classic) |
| Shepherd of Moths | | Mar 2019 | Chaosium | Call of Cthulhu (Classic) |
| Shifters | | 2012 | Stardust Publications | Dark Aeons |
| The Shifting Sands | CT47 | 2011 | Fantasy Flight Games | Call of Cthulhu LCG |
| Shimmering Seas | | Jun 2019 | Chaosium | Call of Cthulhu (Now) |
 Shining Trapezohedron Marker Pack | CW-E15 | 2017 | Petersen Games | Cthulhu Wars |
| Shock Cards | PELGY01SC | 2019 | Pelgrane Press | The Yellow King |
| shoggoth.net | | | Self Published | Call of Cthulhu (Invictus), Call of Cthulhu (Gaslight), Star Wars, Advanced Dungeons and Dragons (Ravenloft), Call of Cthulhu (Strange Aeons) [Future], Call of Cthulhu (Now), Call of Cthulhu (Classic), Paranoia, GURPS |
| The Show Must Go On | | Sep 2023 | Chaosium | Call of Cthulhu (Classic) |
| Shreds and Tatters | | Jul 2019 | Dark Trapezohedron Productions | Call of Cthulhu (Classic) |
| A Shrieking Violet | | Aug 2021 | Chaosium | Call of Cthulhu (Classic) |
| Shub-Niggurath Always Rings Twice | | 2023 | Bolt Thrower Press | Tunnels and Trolls |
| Shub-Niggurath Promo Card * | | 2012 | Fantasy Flight Games | Elder Sign |
| Shuggoth Shuffle Promo Card | | Apr 2008 | Steve Jackson Games | Munchkin |
| Shurgas Mine | | Dec 2022 | Chaosium | Call of Cthulhu (Classic) |
| Sidekicks for Modern Horror - Book 1 | | Sep 2023 | RPG Gamer | Call of Cthulhu (Now) |
| Sidekicks for Modern Horror - Book 2 | | Sep 2023 | RPG Gamer | Call of Cthulhu (Now) |
| Sidekicks for Modern Horror - Book 3 | | Sep 2023 | RPG Gamer | Call of Cthulhu (Now) |
| Sidekicks for Modern Horror - Book 4 | | Sep 2023 | RPG Gamer | Call of Cthulhu (Now) |
| Sidekicks for Modern Horror - Book 5 | | Sep 2023 | RPG Gamer | Call of Cthulhu (Now) |
| Sidekicks for Modern Horror - Book 6 | | Sep 2023 | RPG Gamer | Call of Cthulhu (Now) |
| Sight Unseen * | SKP0833 | 2008 | Skirmisher Publishing | Call of Cthulhu (Classic) |
| The Sign of Glaaki * | EAH08 | 2015 | Fantasy Flight Games | Arkham Horror |
| Signal to Noise | | Jun 2023 | Chaosium | Call of Cthulhu (Now) |
 Signs and Portents | 55 | Apr 2008 | Mongoose Publishing | CthulhuTech |
| Signs and Portents | 56 | May 2008 | Mongoose Publishing | CthulhuTech |
| Signs and Portents | 57 | Jun 2008 | Mongoose Publishing | CthulhuTech |
| Signs and Portents | 58 | Jul 2008 | Mongoose Publishing | CthulhuTech |
| Signs of Blood | | Dec 2022 | Chaosium | Call of Cthulhu (Strange Aeons) [1970s] |
| Signs of Carcosa | EH06 | 2016 | Fantasy Flight Games | Eldritch Horror |
| Silence from Sommerisk | RPG-A1 | 2019 | Petersen Games | Pathfinder |
| The Silence of Eastpoint | | 2020 | Self Published | Dungeons and Dragons |
| Silent Hill * | | 2009 | Tribal Morgue Studios | Call of Cthulhu (Classic) |
| Silent Legions | | 2015 | Sine Nomine Publishing | Silent Legions |
| The Silver Tablet | MAD03 | 2011 | Fantasy Flight Games | Mansions of Madness |
| Simply Cthulhu | | 2019 | Dump Stat Studios | d6 |
| The Sinful Inheritance | | Dec 2021 | Chaosium | Call of Cthulhu (Gaslight) |
| Sinful Season | | 2014 | Self Published | Call of Cthulhu (Delta Green) |
| Sing Sing | | 2006 | Self Published | Call of Cthulhu (Classic) |
| Sink Hole | | 1999 | Self Published | Call of Cthulhu (Now) |
| The Sins of the Father | | Dec 2021 | Chaosium | Call of Cthulhu (Now) |
| Sins of the Flesh | FS04 | 2007 | Self Published | Call of Cthulhu (Rising) |
| Sister of Yhanith'lei | GKG-073 | 2021 | Gallant Knight Games | Tiny Cthulhu |
| Sisters of Doom | | Oct 2023 | Chaosium | Call of Cthulhu (Classic) |
| Sisters Of Sorrow | PELGT29 | 2012 | Pelgrane Press | Trail of Cthulhu |
| Six Spells: Mythos | | 2021 | Skirmisher Publishing | Labyrinth Lord, Mutant Future |
| Skeleton Crew | 5 | 1989 | Argus Specialist Publications | None |
| Skeleton Crew | | Oct 1990 | Argus Specialist Publications | Call of Cthulhu (Now) |
| Skeleton Crew | | Dec 1990 | Argus Specialist Publications | Call of Cthulhu (Now) |
| Skeleton Crew | | Mar 1991 | Argus Specialist Publications | Call of Cthulhu (Now) |
| Skin Deep | | 2022 | Petersen Games | Dungeons and Dragons |
| Skirmish Gaming Tiles | MPS010501A | 2014 | Modiphius Entertainment | Achtung! Cthulhu Skirmish |
| Skirmish Spells Deck | | | Modiphius Entertainment | Achtung! Cthulhu Skirmish |
| Skirmish TAC/Mythos Deck | | | Modiphius Entertainment | Achtung! Cthulhu Skirmish |
| Skirmish: Commander's Set | MUH050454 | 2016 | Modiphius Entertainment | Achtung! Cthulhu Skirmish |
| Skullpips | PCG007 | 2017 | Pleasant Company Games | Ancient Terrible Things |
| Slaves of the Mother | PELGT31 | 2014 | Pelgrane Press | Trail of Cthulhu |
| Slaves of Tsathoggua | SoT | 2016 | Kort'thalis Publishing | Crimson Dragon Slayer |
| The Sleep Experiment | | 2022 | Gallant Knight Games | Tiny Cthulhu |
| Sleep of the Dead | CT30 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG |
| The Sleeper | CW-F2 | 2015 | Petersen Games | Cthulhu Wars |
| The Sleeper Below | CT63 | 2014 | Fantasy Flight Games | Call of Cthulhu LCG |
| A Sliver of Starlight | | Aug 2021 | Chaosium | Call of Cthulhu (Now) |
| A Small Tremor in the Mountains | | Jul 2022 | Chaosium | Call of Cthulhu (Now) |
| Smatter Haulers & Stick Swingers | | May 2021 | Chaosium | Call of Cthulhu (Gaslight) |
| Smell Like a Monster | | 2022 | Petersen Games | Cthulhu Wars |
| Smoke Green | cr6202 | 2019 | Cthulhu Reborn | Call of Cthulhu (Classic) |
| Smoke Green | cr5204 | 2022 | Cthulhu Reborn | Cthulhu Eternal |
| Smoke on the Huangpu | | Sep 2024 | Chaosium | Call of Cthulhu (Classic) |
| Snake Oil Salesman | | Sep 2024 | Chaosium | Call of Cthulhu (Classic) |
| The Snake's Oil | | Apr 2022 | Chaosium | Call of Cthulhu (Gaslight) |
| Snows of an Early Winter | OWC4007 | 2009 | Super Genius | Call of Cthulhu (Now) |
| Sogailraugh | | 2006 | Self Published | Call of Cthulhu (Dark Ages) |
| Sol Noctis | | Apr 2022 | Chaosium | Call of Cthulhu (Classic) |
| Soldiers of Pen and Ink | PELGT36 | 2014 | Pelgrane Press | Trail of Cthulhu |
| Sole Survivor * | APO001 | 2021 | Parts Per Million | APOCTHULHU |
| The Solo Investigators Handbook | | Feb 2019 | 5E Solo Gamebooks | Call of Cthulhu (Classic) |
| Somebody Think of the Children | | Oct 2024 | Chaosium | Call of Cthulhu (Now) |
| Something About Cats | | 2020 | Petersen Games | Cthulhu Wars |
| Song of the Star Walkers | | 2012 | Self Published | Call of Cthulhu (Delta Green) |
| Sorcerer's Apprentice | 7 | Sum 1980 | Flying Buffalo | Tunnels and Trolls |
| Sorcerer's Apprentice | 11 | Sum 1981 | Flying Buffalo | None |
| Sorcerer's Apprentice | 12 | Aut 1981 | Flying Buffalo | None |
| The Sorcerer's Scroll | 25 | 1987 | Self Published | Call of Cthulhu (Classic) |
| Sorrow in Tsavo | | Oct 2020 | Chaosium | Call of Cthulhu (Gaslight) |
| The Sosnovka Raid | | Apr 2021 | Chaosium | Call of Cthulhu (WWII) |
| Soth | | 2015 | Self Published | Soth |
| The Souls of Briarcroft | | Oct 2021 | Chaosium | Call of Cthulhu (Gaslight) |
| Sound and Fury | 4 | | Self Published | Call of Cthulhu (Classic) |
| Sound of the Sea | | Dec 2021 | Chaosium | Call of Cthulhu (Classic) |
| South East London Wargames Group | | | Self Published | Mythos |
| Southern Discomfort * | EDN7201 | 2006 | Eden Studios | Eldritch Skies |
| Space Gamer | 71 | Nov 1984 | Steve Jackson Games | Call of Cthulhu (Classic), Nightmare House |
| Space Gamer | 74 | May 1985 | Steve Jackson Games | The Fantasy Trip, Traveller (Chthonian Stars), Hero System, Call of Cthulhu (Now), Champions, Call of Cthulhu (Classic), Aftermath |
| Space Gamer | 76 | Sep 1985 | Steve Jackson Games | Call of Cthulhu (Classic) |
| Space Gamer | 83 | Oct 1988 | Steve Jackson Games | Call of Cthulhu (Classic) |
| Space Gamer | 86 | Jul 1989 | Steve Jackson Games | Call of Cthulhu (Classic) |
| Space Gamer | 87 | Oct 1989 | Steve Jackson Games | Call of Cthulhu (Classic) |
| Spankham Asylum | cth004 | 2012 | Postmortem Studios | Call of Cthentacle |
| Spark of Life | | Jun 2019 | Chaosium | Call of Cthulhu (Classic) |
 Spawn of Azathoth * | CHA2316-X | 1986 | Chaosium | Call of Cthulhu (Classic) |
| Spawn of Azathoth * | CHA23101 | 2005 | Chaosium | Call of Cthulhu (Classic) |
| Spawn of Madness | | 2006 | Fantasy Flight Games | Call of Cthulhu CCG |
| Spawn of Madness | CT12e | 2011 | Fantasy Flight Games | Call of Cthulhu LCG |
| The Spawn of the Sleeper | CT19 | 2009 | Fantasy Flight Games | Call of Cthulhu LCG |
| The Spawn of Yog-Sothoth | | 1988 | Unknown | The Spawn of Yog-Sothoth |
| The Spear of Y'Golonac | | 2009 | Self Published | Call of Cthulhu (Now) |
| Special Shotguns | | 2012 | Drakat Games | Call of Cthulhu (Classic) |
| Spectral Tides | | Nov 2023 | Self Published | Dark Places and Demogorgons, Call of Cthulhu (Now), GURPS (Horror) |
| Spiralis | | 2018 | Self Published | Spiralis |
| Spirit of a Thief | | 1996 | Self Published | Call of Cthulhu (Now) |
| The Spirit of Liberty | | Apr 2021 | Chaosium | Call of Cthulhu (Gaslight) |
| Spirits & Dreams of the Viking Age | CHA0390 | 2010 | Chaosium | Call of Cthulhu (Dark Ages) |
| The Spirits of London | SFX-3014 | 2017 | Stygian Fox | Call of Cthulhu (Gaslight) |
| Spirits Over Arkham | | 1987 | Self Published | Call of Cthulhu (Classic) |
| Split | | Aug 2022 | Chaosium | Call of Cthulhu (Now) |
| Spoiled Milk | cr6203 | 2019 | Cthulhu Reborn | Call of Cthulhu (Classic) |
| Spoiled Milk | cr5205 | Aug 2022 | Cthulhu Reborn | Cthulhu Eternal |
| The Spoken Covenant | CT36 | 2010 | Fantasy Flight Games | Call of Cthulhu LCG |
| The Spring of Aceso | | 2019 | Golden Goblin Press | Call of Cthulhu (Invictus) |
| Spring-Heeled Jack | WitDBS2 | 2020 | Saturday Morning Scenarios | Whispers in the Dark |
| The Squad Leader | | 2011 | Self Published | CthulhuTech |
| Squamous | | 2017 | Self Published | Squamous |
| St Cecilia's Blasphemous Bordello | | Dec 2021 | Self Published | Call of Cthulhu (Darker Trails), GURPS |
| St Dymphna's Orphanage: Azathoth's Children | | Aug 2021 | Chaosium | Call of Cthulhu (Classic) |
| St Midabaria Clinic | | Jan 2022 | Chaosium | Call of Cthulhu (Classic) |
| St Mormo's Home for Wayward Girls | | Jul 2022 | Chaosium | Call of Cthulhu (Classic) |
| St Raphael's | | 2002 | Self Published | Call of Cthulhu (Classic) |
| Stage Fright at the Playhouse | | Oct 2024 | Chaosium | Call of Cthulhu (Classic) |
| Stained Glass | | 2016 | Xipe Totec Press | Cthulhu Confidential, Trail of Cthulhu, Cthulhu Dark, Call of Cthulhu (Classic), Delta Green |
| The Staircase | | Aug 2021 | Chaosium | Call of Cthulhu (Classic) |
| The Stalking Terror | | 2020 | Micro RPG | The Stalking Terror |
| The Star Brothers | | 2019 | Chaosium | Call of Cthulhu (Classic) |
| The Star Chamber | APU8110 | 2017 | Arc Dream Publishing | Delta Green |
| The Star on the Shore | DCG-SS-HC-1 | 2017 | Dark Cult Games | Call of Cthulhu (Classic) |
| Starchild from Afar | | Feb 2024 | Chaosium | Call of Cthulhu (Classic) |
| Stardate | v3n6 | Jan 1987 | Reluctant Publishing | Call of Cthulhu (Classic) |
| Starfall | | Jun 2019 | Chaosium | Call of Cthulhu (Classic) |
| Stark, Raving Mad! * | | 1991 | Pagan Publishing | Call of Cthulhu (Now), Call of Cthulhu (Classic), Call of Cthulhu (Gaslight) |
| Starlight on the Gutter | cr5101 | 2022 | Cthulhu Reborn | Cthulhu Eternal |
| Starport Helios | | May 2024 | Chaosium | Call of Cthulhu (Strange Aeons) [2370] |
| Starquestor | 1 | | Self Published | Call of Cthulhu (Classic) |
| Starry Wisdom | 1 | Win 1997 | Chaosium | Mythos, None |
| Starry Wisdom | 2 | Spr 1997 | Chaosium | Mythos, Call of Cthulhu (Classic) |
| Starry Wisdom | 3 | Sum 1997 | Chaosium | Call of Cthulhu (Classic), Mythos |
| The Stars Are Also Fire | SM03 | 2007 | Self Published | Call of Cthulhu (Rising) |
| The Stars are Cruel Promo Card | | Oct 2015 | Steve Jackson Games | Munchkin |
| The Stars Are Right | SJG1432 | 2009 | Steve Jackson Games | The Stars Are Right |
| The Stars Are Right! * | CHA2337 | 1992 | Chaosium | Call of Cthulhu (Now) |
| The Stars Are Right! * | CHA23100 | 2004 | Chaosium | Call of Cthulhu (Classic) |
| The Stars Aren't Right | | Apr 2021 | Chaosium | Call of Cthulhu (Strange Aeons) [Future] |
| Stars Over Siberia | | Jan 2024 | Chaosium | Call of Cthulhu (Classic) |
| Starspawn | | 2024 | Petersen Games | Hyperspace |
| Static Protocol | APU8146 | 2021 | Arc Dream Publishing | Delta Green |
| Station S | FXC-16 | 2021 | Stygian Fox | Call of Cthulhu (Classic) |
| The Statue of Athena | BMT-QS1 | 2020 | Halfling Caravan Games | Beta Maxx |
| Statue of the Sorcerer, The Vanishing Conjurer * | CHA2318 | 1986 | Chaosium | Call of Cthulhu (Classic) |
| Stay Away! | | 2014 | Pendragon Game Studio | Stay Away! |
| Stay Away! Promo Set | | 2014 | Ares Games | Stay Away! |
| Stealing Cthulhu | | 2011 | Self Published | Cthulhu Dark |
| Steampunk Cthulhu * | CHA6054 | 2014 | Chaosium | Call of Cthulhu (Steampunk) |
| Stella Clark * | AHC51 | 2020 | Fantasy Flight Games | Arkham Horror: The Card Game |
| The Stench of an Open Grave | | Oct 2023 | Chaosium | Call of Cthulhu (Dark Ages) |
| Step on a Non-Euclidean Brick Toy Promo Card | | Oct 2016 | Steve Jackson Games | Munchkin |
| Sticks and Twigs Like Men | | 2005 | Self Published | Call of Cthulhu (Classic) |
| Sticky Cthulhu | | 2021 | IELLO | Sticky Cthulhu |
| A Sticky Situation | | 2019 | Self Published | Call of Cthulhu (Classic) |
| Stielkrieg | | | Self Published | Call of Cthulhu (Classic) |
| Stinky Orphans! | | Oct 2021 | Chaosium | Call of Cthulhu (Now) |
| Stochastic Sparaogmos | | 2016 | Xipe Totec Press | Trail of Cthulhu, Cthulhu Dark, Call of Cthulhu (Classic), Delta Green, Cthulhu Confidential |
| Stolen Grief | | Aug 2022 | Chaosium | Call of Cthulhu (Classic) |
| A Stone's Throw From Atlantis | | Apr 2021 | Type40 | Call of Cthulhu (Classic) |
| Storm From a Teacup | | Aug 2021 | Chaosium | Call of Cthulhu (Classic) |
| Strain and the Fraying Mind | | 2019 | Self Published | Chthonian Highways |
| Stranded on the North Shore | | Dec 2021 | Chaosium | Call of Cthulhu (Classic) |
| Strange Aeon Game Keeper Edition | FPSAGKE | 2017 | Forever People | Strange Aeon |
| Strange Aeon Game Keeper Visual Aids | SAFPGMVA | 2016 | Forever People | Strange Aeon |
| Strange Aeon Player Edition | SAFPPE | 2017 | Forever People | Strange Aeon |
| Strange Aeons | CHA2353 | 1995 | Chaosium | Call of Cthulhu (Classic) |
| Strange Aeons | | 2009 | Uncle Mike's Worldwide | Strange Aeons |
| Strange Aeons II | CHA23117 | 2009 | Chaosium | Call of Cthulhu (Invictus), Call of Cthulhu (Classic), Call of Cthulhu (Strange Aeons) [2637] |
| Strange Aeons Player's Guide | PZO9000-19E | 2016 | Paizo Publishing | Pathfinder |
| Strange Aeons Poster Map Folio | PZO92100 | 2017 | Paizo Publishing | Pathfinder |
| The Strange and Sunken Fate of Karl Heinrich | | Jul 2019 | Self Published | Call of Cthulhu (Classic), GURPS (Horror) |
| Strange Authorities * | | 2012 | Arc Dream Publishing | Delta Green |
| Strange Carol | | Nov 2023 | Chaosium | Call of Cthulhu (Classic) |
| The Strange Case of Anthony Hanson | | Aug 2022 | Chaosium | Call of Cthulhu (Classic) |
| The Strange Case of Mr Cardew | | Oct 2020 | Chaosium | Call of Cthulhu (Classic) |
| The Strange Cases of Rudolph Pearson * | CHA6042 | 2007 | Chaosium | Call of Cthulhu (Classic) |
| The Strange Dark One * | MRP0019 | 2012 | Miskatonic River Press | None |
| Strange Laws Beyond Out Ken Promo Card | | 2016 | Atlas Games | Lost in R'lyeh |
| Strange Materials | JCG032 | 2019 | Just Crunch Games | The Cthulhu Hack |
| Strange Remnants | EH04 | 2015 | Fantasy Flight Games | Eldritch Horror |
| Strange Songs | CHA0315 | 2005 | Chaosium | Call of Cthulhu (Now) |
| Strange Tales of Dread & Wonder #1 | CHA0329 | 2006 | Chaosium | Call of Cthulhu (Strange Aeons) [1640s, 1960s], Call of Cthulhu (Dark Ages), Call of Cthulhu (Classic) |
| Strange Tales of Dread & Wonder #2 | CHA0330 | 2006 | Chaosium | Call of Cthulhu (Classic), Call of Cthulhu (Now) |
| Stratigraph | CHA23135-Stratigraph | 2016 | Chaosium | Call of Cthulhu (Classic) |
| The Strawman | | Aug 2022 | Chaosium | Call of Cthulhu (Now) |
| Street Chases and Mobs | | 2012 | Self Published | Yellow Dawn |
| Streets of Arkham | MAD25 | 2017 | Fantasy Flight Games | Mansions of Madness |
| Strike! Lovecraftian Adventure | | 2015 | Self Published | Strike! |
| A Study in Emerald * | | 2013 | Treefrog Games | A Study in Emerald |
| A Study in Emerald * | | 2016 | Grey Fox Games | A Study in Emerald |
| A Study in Emerald * | | 2017 | Treefrog Games | A Study in Emerald |
| The Stuff of Nightmares | MUH0010343 | Nov 2023 | Modiphius Entertainment | Achtung! Cthulhu |
| Stunning Eldritch Tales | PELGT02 | 2008 | Pelgrane Press | Trail of Cthulhu |
| Sucker Punch Promo Card | | Aug 2017 | Steve Jackson Games | Munchkin |
| The Sudden Storm | | May 2019 | Chaosium | Call of Cthulhu (Classic) |
| The Suits: Cthulhu | | 2021 | Hornet Games | The Suits: Cthulhu |
| Sukakpak | | 2011 | Self Published | Cthulhu Dark |
| Summon/Bind | | 2016 | Xipe Totec Press | None |
| Summoner's Grimoire | SGPNP001 | 2014 | Voidspiral Entertainment | Summoner's Grimoire |
| Sun Spots | 4 | 2017 | Weird 8 | Call of Cthulhu (Classic) |
| Sun Spots Game Master's Kit | W8_005 | 2018 | Weird 8 | Call of Cthulhu (Classic) |
| Sundown | | 2011 | Imaginary Empire | Call of Cthulhu (Darker Trails) |
| Sunken Dreams | | Jan 2020 | Chaosium | Call of Cthulhu (Classic) |
| Sunken Temple | SAM3 | 2017 | Embers Design Studios | Dungeons and Dragons |
| Sunken Temple | SAM3 | 2017 | Embers Design Studios | Pathfinder |
| Sunken Temple | SAM3 | 2017 | Embers Design Studios | O.L.D. |
| Superheroes Vs The Cthulhu Mythos | | Nov 2020 | Chaosium | Call of Cthulhu (Now) |
| Supressed Memories * | MAD22 | 2016 | Fantasy Flight Games | Mansions of Madness |
| Supressed Transmission The First Transmission * | | 2000 | Steve Jackson Games | GURPS |
| Supressed Transmission The Second Broadcast * | | 2000 | Steve Jackson Games | GURPS |
| Surface Tension | SM02 | 2007 | Self Published | Call of Cthulhu (Rising) |
| Svalbard | TSG0002 | 2021 | NEVR | Svalbard |
 Svalbard Soundtrack | | 2021 | NEVR | Svalbard |
| Swamp Bones | | 1996 | Self Published | Call of Cthulhu (Now) |
| Swamp Song | | Mar 2023 | Chaosium | Call of Cthulhu (Classic) |
| Sweet Shub and Hella Thotep | | 2016 | Liberi Gothica Games | Fate of Cthulhu |
| A Sweet Time of the Year | | Mar 2022 | Chaosium | Call of Cthulhu (Classic) |
| Sweetness | APU8118 | 2018 | Arc Dream Publishing | Delta Green |
| Swords of Cthulhu | | 2022 | BRW Games | Adventures Deep and Dark |
| Sylah-qaulath | | May 2021 | Chaosium | Call of Cthulhu (Classic) |
| Symphony of Madness | | 2024 | Mind's Vision | The Legacy of Cthulhu |