Combat Flight Simulator for LINUX. WW2. Network and VOIP. Open-source.
Odamex is a free, cross-platform, modern client-server Doom engine
Cooperative multiplayer graphical RPG and adventure game
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!
A 2D multiplayer space shooter game
Tools for Super Tux Kart server operators
Cross-platform real-time strategy game (3D)
An unmodified version of the MMORPG Impressive Title by KovuLKD
mGSTEP port of the Cube game engine
Alternative Teeworlds Client with many exciting features!
WeComeInPeace is a simple RTS game that aims towards multiplayer
Multiplayer Rogue-like combat game
C/C++ , PHP, PYTHON, 3D ENGINES, CHROME NATIVE CLIENT
3D Space Station Simulator (inspired by SS13)
starrydb is game server engine