Godot Engine – Multi-platform 2D and 3D game engine

Turbulenz is a modular 3D and 2D game framework for making HTML5 powered games for browsers, desktops and mobile devices.

A completely free, open-source, 2D game engine built on proven torque technology.

A powerful free cross-platform RTS game engine. - Report issues at https://springrts.com/mantis/

Cocos2d-x is a suite of open-source, cross-platform, game-development tools utilized by millions of developers across the globe. Its core has evolved to serve as the foundation for Cocos Creator 1.…

The Cross Platform Game Engine

Open-source, cross-platform, C++ game engine for creating 2D/3D games.

A complete 3-D game development suite written in Java.

Free (as in freedom) open source clone of the Age of Empires II engine 🚀

One framework for creating powerful cross-platform games.

Desktop/Android/HTML5/iOS Java game development framework

🐙 Superpowers — Extensible HTML5 app for real-time collaborative projects

The Atomic Game Engine is a multi-platform 2D and 3D engine with a consistent API in C++, C#, JavaScript, and TypeScript

🎮 Open-source, cross-platform game engine designed to be used by everyone.

Game engine

Real-Time Strategy game 3D engine coded in pure java

Phaser is a fun, free and fast 2D game framework for making HTML5 games for desktop and mobile web browsers, supporting Canvas and WebGL rendering.

a fresh, modern & lightweight HTML5 game engine

Babylon.js is a powerful, beautiful, simple, and open game and rendering engine packed into a friendly JavaScript framework.