3D Game engine
2D physics engine for games
C++ OpenSource Game Fabric based on SDL2
2D XNA Game Engine
Yet another game engine
Visual Novel engine, editor and game development.
Text Based Game Engine and Parser
TurboSphere is an easy to learn and powerful JS based game engine.
A 2D game engine base on OpenGL and SDL,support for Windows & Linux
Java Game Engine
A Game Engine
A free ActionScript 3 library designed for developing 2D Flash games
A point-n-click adventure game engine for GameMaker: Studio
A multiplatform game engine for interactive fiction experiences
A 3D, fully concurrent game engine
A 3d game engine on stage3D
Free Android 2D OpenGL Game Engine