Xash3D FWGS engine
Multi Theft Auto is a game engine
fheroes2 is a recreation of Heroes of Might and Magic II game engine
Powerful, mature open-source cross-platform game engine for Python
Cocos simplifies game creation and distribution with Cocos Creator
Voxel game engine in C++ with OpenGL
Stride (formerly Xenko), a free and open-source cross-platform C# game
Cross-Platform C++ 2D/3D game engine
The game engine for everyone
Solar2D Game Engine main repository (ex Corona SDK)
Descent 3 by Outrage Entertainment
The flexible game engine
Open-source engine for Heroes of Might and Magic III
Voxel game-creation platform with easy modding and game creation
Cross-platform 2D and 3D game engine with modular architecture
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
Free game engine for development of desktop, mobile, and web games
Open source clone of the Age of Empires II engine
A pure Go game engine
3D Procedural Game Engine Using OpenGL
A multi core friendly rigid body physics and collision detection lib
The Open Toolkit library is a fast, low-level C# wrapper for OpenGL
A game engine with an emphasis on real-time cutting-edge solutions