The Tiny JavaScript Game Engine That Can!
Voxel game-creation platform with easy modding and game creation
A retro game engine for Python
Open-source engine for Heroes of Might and Magic III
Magic Another Game Engine
Free game engine for development of desktop, mobile, and web games
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Open source clone of the Age of Empires II engine
Open source library for creative expression on the web, desktop, etc.
The ioquake3 community effort to continue supporting/developing id's
Fast and lightweight JavaScript game engine built on WebGL and glTF
The game engine for everyone
Python MUD/MUX/MUSH/MU* development system
Cocos simplifies game creation and distribution with Cocos Creator
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
2D JavaScript Physics Engine
Open game and rendering engine packed into a JavaScript framework
Xash3D FWGS engine
A high-performance, industry-standard 2D physics engine built on Box2D
A completely free, open-source, 2D game engine
A dead simple 2D game engine for Go
3D game engine/framework in C, with Luajit and Python bindings now
KorGE Game Engine. Multiplatform Kotlin Game Engine & Korlibs
Cross-platform game engine in Rust
3D and 2D game engine written in Rust