Free game engine for development of desktop, mobile, and web games
The Tiny JavaScript Game Engine That Can!
A completely free, open-source, 2D game engine
JavaScript-based game engine designed to empower developers
MIT Licensed Open Source version of Torque3D from GarageGames
Web powered cross-platform 3D, WebXR game engine
Godot is a fully featured, open source, MIT licensed, game engine.