Odamex is a free, cross-platform, modern client-server Doom engine
0 A.D. is a free, open-source, cross-platform real-time strategy game.
A fun realistic multiplayer free-and-open-source first-person-shooter!
GameServer is a sophisticated, game server designed for online games
The world is no longer the same
A 2D multiplayer space shooter game
tour based strategic game
Visual Basic 6 2D online adventure game engine
A free 3d game for PC that does not limit the player. Fight,Build,Gain
Cross-platform real-time strategy game (3D)
LGSL (Live Game for PHP 5.4-8+: online status for various gameservers
Free and open source Avatar Webgame made by Vietnam
An online multiplayer real time strategy game
FreeCS is a free-software reimplementation of Counter-Strike 1.5.
oGame-like browser space realtime strategy game based on xNova
An open-source, multiplayer fps based on Cube 2 Engine.
C/C++ , PHP, PYTHON, 3D ENGINES, CHROME NATIVE CLIENT
starrydb is game server engine
Clone of Urban Assault with new Graphics.
A collection of all maps and games made for the TripleA game engine
Java decentralized cross-platform network multiplayer game engine
Free strategy browsergame engine.