Cross-platform 2D and 3D game engine with modular architecture
Multi-platform Engine for Desktop, XBOX (UWP) and Mobile games
Voxel game engine in C++ with OpenGL
dhewm 3 main repository
Free game engine for development of desktop, mobile, and web games
scene-oriented, flexible 3D engine (C++, Python, C#, Java)
GemRB is a portable open-source implementation of the Infinity Engine
Vivid is a modern C++ 3D engine using OpenGL4+
3D C++ Game Engine - yet another open source game engine
Amazon Lumberyard is a free AAA game engine
2D Game Engine
2D Game Engine with Lua Scripting made on top of SFML
A cross-platform 2D game engine
Portable game engine with main focus on point-and-click adventures
Mahasona engine is an open source game engine.
Gorgon Game Engine (GGE) is a C++ game engine that handles many tasks.
2D physics engine for games
3D game engine for C and C++
A DirectX based graphics/physics engine
Zen3D is a 3D engine and editor for creating games