Xash3D FWGS engine
Free, cross-platform 2D game engine powered by Haxe and OpenFL
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
A dead simple 2D game engine for Go
GemRB is a portable open-source implementation of the Infinity Engine
Cross-platform 2D game engine (+ full OpenGL, +full OpenGL ES )
Orx: Data-Driven Game Engine
A Complete WebGPU Game Engine for Browser & Desktop Arcade Oriented
Real-time RPG for PC/tablet/phone; multiple quests and random dungeons
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