Godot is a powerful cross-platform game engine
Open source voxel game engine with support for survival and crafting
The game engine for everyone
Xash3D FWGS engine
Open source library for creative expression on the web, desktop, etc.
The ioquake3 community effort to continue supporting/developing id's
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
New Godot bindings for Swift
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Voxel game-creation platform with easy modding and game creation
dhewm 3 main repository
Cocos simplifies game creation and distribution with Cocos Creator
Stride (formerly Xenko), a free and open-source cross-platform C# game
JavaScript-based game engine designed to empower developers
A dead simple 2D game engine for Go
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Multi-platform 2D and 3D game engine
Real Time Strategy game engine supporting early Westwood classics
Cross-platform game engine in Rust
Voxel game engine in C++ with OpenGL
Fast and lightweight JavaScript game engine built on WebGL and glTF
A Flutter based game engine
Free game engine for development of desktop, mobile, and web games
Cross-platform 2D and 3D game engine with modular architecture
The Tiny JavaScript Game Engine That Can!