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