scene-oriented, flexible 3D engine (C++, Python, C#, Java)
The flexible game engine
Animation Compression Library
a UCI chess engine
2D Game Engine with Lua Scripting made on top of SFML
KlayGE is a cross-platform open source game engine
Portable game engine with main focus on point-and-click adventures
Intrinsic is a Vulkan based cross-platform game and rendering engine
Gorgon Game Engine (GGE) is a C++ game engine that handles many tasks.
A Simple Game Engine
2D Game Engine, based on OpenGL and focused on Isometric Games
Cross-platform 2D game engine