Unofficial Doom-based and Doom-related games and mods have been written by fans.
Games
- END OF DOOM
- cDoom
- Chacal 3D
- Damnation (a Flash game)
- Doom 2D
- Doom 2D - Knee deep in the dead
- MiniDOOM
- Doom 2 pinball for Visual Pinball v6.1 or better
- Doom89, for Texas Instruments models 89, 92+, and V200
- Doomed (a Flash game)
- Doom: Fall of Mars
- Doom: Gates of Hell
- Doom-like minigame
- Doom Reloaded
- Doom Role-Playing Game
- Doom: The Battle For Mars
- Doom: The Next Chapter
- Doom, the Roguelike
- Enter the Doom Chapter I: Lucido Attack
- FOOM!
- Freedoom
- Hell Commander
- PocketStation DOOM
- Doom Wars: UAC vs. Hell
- Doom Triple Pack - Compilation of demo/shareware versions Doom, Heretic and Hexen in Flash
Mods
- Classic Doom for Doom 3
- Doom ModPack for Civilization II
- Dungeon Doom
- Generations Arena
- Korax Mod
- Unreal Doom for Unreal Tournament
- Wolfendoom
- DOOM: Legions of Hell
- Your Path of Destruction
- Zombie Slayer
- Prometheus DOOM 3 Movie Mod
- Blade Yautja
Non-Doom games using the Doom engine
- Action Doom 2
- Chex Quest 3
- Foreverhood (in development)
- Harmony
- Mega Man 8-Bit Deathmatch
- Sonic Robo Blast 2 (in Active development,Version 2.1.X is out ...)
- Super 3D Pig Feeder