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