Godot is a powerful cross-platform game engine
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Xash3D FWGS engine
The game engine for everyone
Multi-platform 2D and 3D game engine
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
A dead simple 2D game engine for Go
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Cocos simplifies game creation and distribution with Cocos Creator
Open source library for creative expression on the web, desktop, etc.
New Godot bindings for Swift
Cross-platform game engine in Rust
A Complete WebGPU Game Engine for Browser & Desktop Arcade Oriented
GemRB is a portable open-source implementation of the Infinity Engine
Orx: Portable Game Engine
Urho3D Game engine
Cross-platform 2D and 3D game engine
The Atomic Game Engine is a multi-platform 2D and 3D engine
Open-source, cross-platform, C++ game engine for creating 2D/3D games
Modern AS3 Game Engine
Cross platform 2D/3D game engine written in C++11 & OpenGL ES 2/3
Egret is a brand new open mobile game and application engine
2D physics engine for games