Godot is a powerful cross-platform game engine
Fast and lightweight JavaScript game engine built on WebGL and glTF
Multi-platform 2D and 3D game engine
Cocos simplifies game creation and distribution with Cocos Creator
Xash3D FWGS engine
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Cross-Platform C++ 2D/3D game engine
The flexible game engine
A game engine with an emphasis on real-time cutting-edge solutions
An OpenGL RTS game engine written in C
Zig game engine & graphics toolkit
Cross-platform 2D and 3D game engine with modular architecture
Solar2D Game Engine main repository (ex Corona SDK)
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
A complete 3-D game development suite written in Java
Open source voxel game engine with support for survival and crafting
The Ren'Py Visual Novel Engine
LayaAir is an open-source 2D/3D engine
Recreation of the classic Grand Theft Auto III game executable
Multi Theft Auto is a game engine
A game engine powered by python and panda3d
Voxel game engine in C++ with OpenGL
The ioquake3 community effort to continue supporting/developing id's
Voxel game-creation platform with easy modding and game creation
A completely free, open-source, 2D game engine