| Title | Pages | Publication | Code | Date | Publisher | |
|---|---|---|---|---|---|---|
 Xanthophobia | Event (C) |  Arkham Edition | 2004 | Fantasy Flight | ||
 Xebi Co |  Xebi Co | 2020 | Chaosium | |||
 Xeno-archaeology! |  Ken Writes About Stuff | v2n5 | Jul 2014 | Pelgrane Press | ||
| Xlizxcte-Oonth | Character (F) | The Thousand Young | CT65 | 2015 | Fantasy Flight | |
| Xmas in Arkham | 18-? |  PerChance | 7 | Dec 1991 | Self Published | |
 X-Mythos | Chaosium Digest | v12n07 | Dec 1995 | Chaosium | ||
| Xo Tl'mi-go | Jun 2006 |  shoggoth.net | n/a | Self Published | ||
 Xothian Acolytes Box | Xothian Acolytes Box | 2017 | GobboTown Games | |||
| Xothian Greater Terrorbeast Box | Xothian Greater Terrorbeast Box | 2017 | GobboTown Games | |||
| Xothian Guard Box | Xothian Guard Box | 2017 | GobboTown Games | |||
| Xothian Lesser Terrorbeast Box | Xothian Lesser Terrorbeast Box | 2017 | GobboTown Games |