Solar2D Game Engine main repository (ex Corona SDK)
Desktop/Android/HTML5/iOS Java game development framework
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Cocos simplifies game creation and distribution with Cocos Creator
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Multi-platform 2D and 3D game engine
Voxel game-creation platform with easy modding and game creation
Free game engine for development of desktop, mobile, and web games
Flax Engine, multi-platform 3D game engine
3D Game engine with editor
3D Procedural Game Engine Using OpenGL
GemRB is a portable open-source implementation of the Infinity Engine
3D modeler, 3D game maker, 3D demo maker
GameServer is a sophisticated, game server designed for online games
A free Chess program for Windows with a large set of features
Orx: Data-Driven Game Engine
0 A.D. is a free, open-source, cross-platform real-time strategy game.
A promising chess program
Combat Flight Simulator for LINUX. WW2. Network and VOIP. Open-source.
Urho3D Game engine
Spring is a free RTS engine developed for Windows, Linux and Mac OS X.
3D C++ Game Engine - yet another open source game engine
Cross-platform 2D and 3D game engine
A 2D game engine and level editor