Cross-Platform OpenGL Doom Source Port with powerful modding features

Eureka is a cross-platform map editor for the DOOM engine games.

Quake Essentials. Better than what a licencee of id would get in 1996. For even more goodness to base your game off of, see https://github.com/VeraVisions/nuclide

Main Repo for "Aetherius" (for Doom1/2 w/ GZDoom)

"Explosive Expedition" Character/RPG modification based on the character Dinah Wyck from Dynamite Duchess/Appetite For Detention/Carnival of Souls, for GZDoom. No mod-specific ACS unlike Aetherius, only ZScript :V

DOOM 1 & 2 .wad tools for creating and extracting wad files (WIP)

Biff Fraggar is a Freedoom-inspired id Tech 1 game under the GPL license.