Open 3D Engine (O3DE) is an Apache 2.0-licensed multi-platform 3D
A modular Common Lisp game engine
Open source library for creative expression on the web, desktop, etc.
Modified source engine (2017) developed by valve and leaked in 2020
Entitas is a super fast Entity Component System (ECS) Framework
Amazon Lumberyard is a free AAA game engine
2D Game Engine with Lua Scripting made on top of SFML
Web powered cross-platform 3D, WebXR game engine
OpenSAGE is a free, open source re-implementation of SAGE
Multi-platform game engine similar to old Megaman with a stage editor
C++ OpenSource Game Fabric based on SDL2