Alternatives and similar repositories for three:

Users that are interested in three are comparing it to the libraries listed below

• ioquake / launch
  The launcher for ioquake3.
  ☆38Updated 9 years ago
• ioquake / jedi-outcast
  ☆53Updated 6 years ago
• ioquake / jedi-academy
  ☆53Updated 11 years ago
• videogamepreservation / mechcommander2
  MechCommander 2 (2001) by FASA Studio
  ☆39Updated 8 years ago
• videogamepreservation / marathon2
  Marathon 2: Durandal (1995) by Bungie Software Products Corporation
  ☆31Updated 9 years ago
• videogamepreservation / jediacademypc
  Star Wars: Jedi Knight - Jedi Academy (2003) by Raven Software Corporation
  ☆34Updated 12 years ago
• NightDive-Studio / strife-ve
  Strife Veteran Edition GPL Source Release
  ☆46Updated 3 years ago
• videogamepreservation / arxfatalis
  Arx Fatalis (2002) by Arkane Studios SA
  ☆24Updated 12 years ago
• videogamepreservation / blood2
  Blood II: The Chosen (1998) by Monolith Productions, Inc.
  ☆52Updated 10 years ago
• 3dfxdev / EDGE
  EDGE Source Code
  ☆75Updated 2 years ago
• xythobuz / OpenRaider
  Open Source Tomb Raider Engine
  ☆83Updated 11 months ago
• videogamepreservation / swars
  Syndicate Wars Port is a port of the 1996 DOS game Syndicate Wars to modern operating systems.
  ☆23Updated 10 years ago
• OpenSourcedGames / Heretic
  ☆46Updated 12 years ago
• CatacombGames / TheCatacomb
  Catacomb 2 source code
  ☆71Updated 10 years ago
• CatacombGames / CatacombArmageddon
  Catacomb Armageddon source code
  ☆37Updated 10 years ago
• videogamepreservation / sevenkingdoms
  Seven Kingdoms: Ancient Adversaries (1998) by Enlight Software Ltd.
  ☆10Updated 9 years ago
• videogamepreservation / starcontrol2
  Star Control II (1992) by Toys for Bob Inc.
  ☆25Updated 9 years ago
• miohtama / aliens-vs-predator
  Aliens vs. Predator Gold source code
  ☆36Updated 12 years ago
• videogamepreservation / theoperative
  The Operative: No One Lives Forever (2000) by Monolith Productions, Inc.
  ☆24Updated 9 years ago
• videogamepreservation / hexen
  Hexen: Beyond Heretic (1995) by Raven Software
  ☆48Updated 9 years ago
• omcfadde / dante
  idTech4 OpenGL ES2.0 | #dante (irc.freenode.net)
  ☆112Updated 12 years ago
• hackcraft-de / linwarrior
  Linwarrior 3D - public repository backup for the open source mech simulation game
  ☆33Updated last year
• ZDoom / qzdoom
  Experimental fork that tries out daring and cutting edge features. Forked from here - https://github.com/zdoom/gzdoom
  ☆71Updated 2 years ago
• clover-moe / mint-arena
  Spearmint Quake 3 and Team Arena game code.
  ☆40Updated 2 months ago
• TTimo / bspc
  Quake 3 BSP-to-AAS compiler
  ☆31Updated last year
• CatacombGames / CatacombAbyss
  Catacomb Abyss source code
  ☆83Updated 10 years ago
• dos-games / vanilla-shadow_warrior
  Official source release for Shadow Warrior
  ☆21Updated 10 years ago
• videogamepreservation / wolf3d
  Wolfenstein 3D (1992) by id Software, Inc. for DOS
  ☆21Updated 13 years ago
• videogamepreservation / postal
  Postal (1997) by Running With Scissors
  ☆42Updated 8 years ago
• camgunz / d2k
  A Doom Source Port for the 20th Century
  ☆18Updated 3 years ago