[–] luthis 0 points 3 points 3 points (+3|-0) ago (edited ago)
0 A.D. Basically FOSS Age of Empires
OpenMW Open source Morrowind (you still need the original game data though, but technically the engine is open source so it counts)
Arx Libertatis Arx Fatalis remade for Linux
[–] Vladar 0 points 3 points 3 points (+3|-0) ago
Battle for Wesnoth Turn-based tactical strategy.
Cataclysm: Dark Days Ahead Complex post-apocalyptic survival roguelike.
Hedgewars Nicely done Worms clone.
Brogue Original take on roguelike genre.
[–] [deleted] 0 points 6 points 6 points (+6|-0) ago
[–] unixfreak 0 points 2 points 2 points (+2|-0) ago (edited ago)
OpenRA (C&C Red Alert clone)
Red Eclipse (Arena shooter like unreal/quake with parkour and multiplayer map ediiting)
Sauerbraten (Fast paced quake like shooter, which Red Eclipse is forked from)
Frogatto & Friends (Pixel art 2d platformer featuring a frog)