Godot is a powerful cross-platform game engine
Multi Theft Auto is a game engine
The Ren'Py Visual Novel Engine
Real Time Strategy game engine supporting early Westwood classics
Xash3D FWGS engine
fheroes2 is a recreation of Heroes of Might and Magic II game engine
The game engine for everyone
Open-source engine for Heroes of Might and Magic III
Cocos simplifies game creation and distribution with Cocos Creator
A game engine powered by python and panda3d
Open source voxel game engine with support for survival and crafting
A complete 3-D game development suite written in Java
Fast and lightweight JavaScript game engine built on WebGL and glTF
Voxel game-creation platform with easy modding and game creation
Multi-platform 2D and 3D game engine
Solar2D Game Engine main repository (ex Corona SDK)
A refreshingly simple data-driven game engine built in Rust
Descent 3 by Outrage Entertainment
dhewm 3 main repository
Free, cross-platform 2D game engine powered by Haxe and OpenFL
LayaAir is an open-source 2D/3D engine
Powerful, mature open-source cross-platform game engine for Python
3D Procedural Game Engine Using OpenGL
Free game engine for development of desktop, mobile, and web games
3D Game engine with editor