scene-oriented, flexible 3D engine (C++, Python, C#, Java)
Vivid3D is a C++ IDE/3D engine, with python scripting.
2D Game Engine
A 2D game engine and level editor
Multi-platform game engine similar to old Megaman with a stage editor
A roguelike game engine/editor
3D Game engine
A Simple Game Engine
cross-platform 2d game engine
Zen3D is a 3D engine and editor for creating games