A MegaCollection Kits
The original FPS
Classic id Tech 0 Games
Wolfenstein 3D (Expansion: Spear of Destiny)
Blake Stone: Aliens of Gold, Blake Stone: Planet Strike, Rise of the Triad: Dark War, Super 3D Noah's Ark
For Wolfenstein: Wolf4SDL is the definitive one. Alternativley, use ECWolf or fork LZWolf. ECWolf powers the official Super 3D Noah's Ark rereleases. Reflection Keen also supports Keen Dreams and Catacomb 3D.
BStone for Blake Stone and rottexpr or WinRott/WinRottAPI/GLRott for Rise of the Triad. Note that the latter is very old.
Alternativley, Return of the Triad is a Doom TC, or you can play online in Wolf3D.net.
Klooni is a recreation of Doom. SplitWolf adds local multiplayer. Green Arrow is based on the comics and TV. Spear Resurrection and Spear End of Destiny are fan sequels. Project: X Insurrection is about fighting vampires. Project Totengraeber is a classic. Unsung is a WW1 story. Witching Hour is survival horror. The Orb of Dilaaria is fantasy-themed.
Wolf3D.net hosts a database of links on their Games Page
WDC (Itch.io) is among the best for Wolf4SDL. VSWolfTools 2 is actually 4 seperate programs. Havoc's Wolf3D Editor can edit multiple Wolf3D games. MapEdit is the most popular DOS-based map editor. TED5 (Source code) was used by id to make the original maps.
Wolf3D.net Guides Page
Wolfenstein 3D Vault, Wolfenstein 3-D Dome
C-Dogs SDL (mentioned in Freeware) can turn Wolfenstein maps into top-down shooters.
Neocities: Dannarchy (Rise of the Triad page)
Background taken from here.