Godot is a powerful cross-platform game engine
Open source voxel game engine with support for survival and crafting
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
The game engine for everyone
Voxel game-creation platform with easy modding and game creation
Xash3D FWGS engine
Solar2D Game Engine main repository (ex Corona SDK)
Free, cross-platform 2D game engine powered by Haxe and OpenFL
Open-source engine for Heroes of Might and Magic III
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Cocos simplifies game creation and distribution with Cocos Creator
New Godot bindings for Swift
A dead simple 2D game engine for Go
Cross-platform game engine in Rust
Multi-platform 2D and 3D game engine
Open source library for creative expression on the web, desktop, etc.
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
KorGE Game Engine. Multiplatform Kotlin Game Engine & Korlibs
A completely free, open-source, 2D game engine
Multi Theft Auto is a game engine
The Ren'Py Visual Novel Engine
fheroes2 is a recreation of Heroes of Might and Magic II game engine
Open game and rendering engine packed into a JavaScript framework
A complete 3-D game development suite written in Java
A game engine powered by python and panda3d