Godot is a powerful cross-platform game engine
Xash3D FWGS engine
Open source voxel game engine with support for survival and crafting
Voxel game-creation platform with easy modding and game creation
The game engine for everyone
The Ren'Py Visual Novel Engine
Multi Theft Auto is a game engine
Real Time Strategy game engine supporting early Westwood classics
A game engine powered by python and panda3d
Free game engine for development of desktop, mobile, and web games
LayaAir is an open-source 2D/3D engine
Fast and lightweight JavaScript game engine built on WebGL and glTF
Free, cross-platform 2D game engine powered by Haxe and OpenFL
A complete 3-D game development suite written in Java
The flexible game engine
A refreshingly simple data-driven game engine built in Rust
Cocos simplifies game creation and distribution with Cocos Creator
A modular Common Lisp game engine
Voxel game engine in C++ with OpenGL
fheroes2 is a recreation of Heroes of Might and Magic II game engine
Open-source engine for Heroes of Might and Magic III
RPG Maker 2000/2003 and EasyRPG games interpreter
The ioquake3 community effort to continue supporting/developing id's
Open source clone of the Age of Empires II engine
dhewm 3 main repository