Xash3D FWGS engine
Godot is a powerful cross-platform game engine
Open source voxel game engine with support for survival and crafting
Voxel game-creation platform with easy modding and game creation
The game engine for everyone
Cocos simplifies game creation and distribution with Cocos Creator
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Solar2D Game Engine main repository (ex Corona SDK)
Cross-platform game engine in Rust
Free, cross-platform 2D game engine powered by Haxe and OpenFL
dhewm 3 main repository
Real Time Strategy game engine supporting early Westwood classics
A dead simple 2D game engine for Go
Open source library for creative expression on the web, desktop, etc.
New Godot bindings for Swift
Open-source engine for Heroes of Might and Magic III
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
KorGE Game Engine. Multiplatform Kotlin Game Engine & Korlibs
Multi-platform 2D and 3D game engine
A completely free, open-source, 2D game engine
Kotlin extensions for the libGDX game framework
GemRB is a portable open-source implementation of the Infinity Engine
A modern, cross-platform Quake game engine based on FitzQuake.
Cross-platform 2D game engine (+ full OpenGL, +full OpenGL ES )
Orx: Data-Driven Game Engine