Multi Theft Auto is a game engine
Xash3D FWGS engine
Cocos simplifies game creation and distribution with Cocos Creator
Open-source engine for Heroes of Might and Magic III
Voxel game-creation platform with easy modding and game creation
Descent 3 by Outrage Entertainment
Stride (formerly Xenko), a free and open-source cross-platform C# game
The game engine for everyone
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Powerful, mature open-source cross-platform game engine for Python
Voxel game engine in C++ with OpenGL
fheroes2 is a recreation of Heroes of Might and Magic II game engine
The Open Toolkit library is a fast, low-level C# wrapper for OpenGL
Free game engine for development of desktop, mobile, and web games
Cross-Platform C++ 2D/3D game engine
Solar2D Game Engine main repository (ex Corona SDK)
dhewm 3 main repository
The ioquake3 community effort to continue supporting/developing id's
Open source clone of the Age of Empires II engine
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
A game engine with an emphasis on real-time cutting-edge solutions
A completely free, open-source, 2D game engine
A pure Go game engine
3D Game engine with editor
Go bindings for raylib, a simple and easy-to-use library