Mangos ZERO is a server for World of Warcraft
Doom-based AI research platform for reinforcement learning
Cross-platform 2D and 3D game engine with modular architecture
A cross-platform PSP emulator
Free and open source real-time strategy game
Cross-Platform C++ 2D/3D game engine
Open Source MMORPG Framework
Powerful, mature open-source cross-platform game engine for Python
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Voxel game-creation platform with easy modding and game creation
Cocos simplifies game creation and distribution with Cocos Creator
Desktop/Android/HTML5/iOS Java game development framework
Tool to statically recompile N64 games into native executables
Recreation of the classic Grand Theft Auto III game executable
Stream switch games to your PC via USB or network
An unofficial PC port of the Xbox 360 version of Sonic Unleashed
Free game engine for development of desktop, mobile, and web games
Classic 2D side-scrolling platformer game
Descent 3 by Outrage Entertainment
3D Procedural Game Engine Using OpenGL
Open source clone of the Age of Empires II engine
Voxel game engine in C++ with OpenGL
The game engine for everyone
Solar2D Game Engine main repository (ex Corona SDK)
Source code repository of the FreeOrion project