Endless Sky is a sandbox-style space exploration game
Real Time Strategy game engine supporting early Westwood classics
Open source clone of the Age of Empires II engine
Widelands is a free, open source real-time strategy game
RTS game with the theme of Strategy by Design
Arianne is an engine to develop multiplayer online games like Stendhal
Seven Kingdoms: Ancient Adversaries
Europa Universalis 4 save game editor
Cross-platform, GPL reimplementation of the classic : Syndicate
Real-time Strategy
0 A.D. is a free, open-source, cross-platform real-time strategy game.
Online War system for IL-2 Sturmovik and Iron Front in ArmA 2
Snake Feast is a fun, addictive arcade game where you control a snake
RTSish Game Engine
The classic multiplayer strategy game for use as a BBS door
A free 3d game for PC that does not limit the player. Fight,Build,Gain
Open source FPS/RTS Game
Utilities to make running a MegaMek server easier
Mech Station Beta - Tower Defense like Game
An enhanced version of 7K:AA (Seven Kingdoms: Ancient Adversaries).
Cross-platform real-time strategy game (3D)