Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
Cross-platform 2D and 3D game engine with modular architecture
Free game engine for development of desktop, mobile, and web games
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
A modular Common Lisp game engine
Stride (formerly Xenko), a free and open-source cross-platform C# game
The multiplayer game engine
Vivid is a modern C++ 3D engine using OpenGL4+
3D C++ Game Engine - yet another open source game engine
Data-oriented and data-driven game engine written in Rust