Alien Arena is a fast, free FPS deathmatch game.

OpenArena is a free and open-source video game, it is first-person shooter (FPS) and a video game clone of Quake III Arena.

Cube 2: Sauerbraten ("sour roast", or Sauer) is a cross-platform, Quake-like first-person shooter that runs on Microsoft Windows, Linux, FreeBSD and Mac OS X …

Unreal Tournament is a first-person shooter video game.

Warsow, also stylized as War§ow, is an open source first-person shooter video game.

AssaultCube (ActionCube) is a free and open source software first-person shooter video game.

Quake is a series of first-person shooter video games, starting with the game of the same name.

Tremulous is a free and open source team-based first-person shooter with real-time strategy elements.

Unvanquished is an opensource first-person strategy shooter game.

Xonotic is a free and open-source first-person shooter video game.