Cocos simplifies game creation and distribution with Cocos Creator
Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
Open game and rendering engine packed into a JavaScript framework
Various things for PSX (PlayStation 1, PSone)
Voxel game engine in C++ with OpenGL
UZDoom is a feature centric port for all Doom engine games
Cross-Platform C++ 2D/3D game engine
Java/JavaFX/Kotlin Game Library (Engine)
Cross-platform 2D and 3D game engine with modular architecture
Stride (formerly Xenko), a free and open-source cross-platform C# game
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
A Minecraft mapping tool that creates 3D models of your Minecraft
Multi-platform 2D and 3D game engine
A modular Common Lisp game engine
Open source library for creative expression on the web, desktop, etc.
DeSmuME is a Nintendo DS emulator
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Zig game engine & graphics toolkit
3D and 2D game engine written in Rust
Cross-platform game engine in Rust
One framework for creating powerful cross-platform games
IsoCity: City building simulation game
Powerful, mature open-source cross-platform game engine for Python
A real-time 3D Engine written in Ada