Simple and easy 3D engine for LÖVE
Cross-platform 2D and 3D game engine
3D-Accelerated open-source DOOM engine
A 3D Game Framework
action/combat flight sim
sauerbraten with LuaJit2 scripting
Pear3DEngine is a modern and modular 3D development framework
A complete 2D Game Engine with built in drag and drop editor
A 3D rendering / entity engine