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
Cross-platform game engine in Rust
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Solar2D Game Engine main repository (ex Corona SDK)
dhewm 3 main repository
A dead simple 2D game engine for Go
Real Time Strategy game engine supporting early Westwood classics
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