Godot is a powerful cross-platform game engine
Xash3D FWGS engine
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Voxel game-creation platform with easy modding and game creation
Cocos simplifies game creation and distribution with Cocos Creator
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Open source library for creative expression on the web, desktop, etc.
Cross-platform game engine in Rust
The game engine for everyone
A dead simple 2D game engine for Go
Cross-platform 2D game engine (+ full OpenGL, +full OpenGL ES )
Cross-platform 2D and 3D game engine
Real-time RPG for PC/tablet/phone; multiple quests and random dungeons
Multi-threaded game engine for Android
The Atomic Game Engine is a multi-platform 2D and 3D engine
Open-source, cross-platform, C++ game engine for creating 2D/3D games
Cross platform 2D/3D game engine written in C++11 & OpenGL ES 2/3
cross-platform 2d game engine
Cross-platform 2D game engine