Godot is a powerful cross-platform game engine
Xash3D FWGS engine
Multi Theft Auto is a game engine
The Ren'Py Visual Novel Engine
The game engine for everyone
Open source voxel game engine with support for survival and crafting
A game engine powered by python and panda3d
Solar2D Game Engine main repository (ex Corona SDK)
fheroes2 is a recreation of Heroes of Might and Magic II game engine
Open-source engine for Heroes of Might and Magic III
A retro game engine for Python
A complete 3-D game development suite written in Java
Voxel game-creation platform with easy modding and game creation
Real Time Strategy game engine supporting early Westwood classics
Fast and lightweight JavaScript game engine built on WebGL and glTF
dhewm 3 main repository
Open source clone of the Age of Empires II engine
Powerful, mature open-source cross-platform game engine for Python
The ioquake3 community effort to continue supporting/developing id's
Magic Another Game Engine
An OpenGL RTS game engine written in C
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
RPG Maker 2000/2003 and EasyRPG games interpreter
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
A refreshingly simple data-driven game engine built in Rust