RPG Maker 2000/2003 and EasyRPG games interpreter
GemRB is a portable open-source implementation of the Infinity Engine
2D Game Engine
An open source re-implementation of Diablo 2
A fast, scalable, distributed game server engine/framework for C++
A space race game in the style of A Dark Room
A 2D Adventure Game & Engine
TurboSphere is an easy to learn and powerful JS based game engine.
Role Playing Game Engine
A retro style video game engine for RPGs and adventure games.
Java Client + JS/Canvas Server-Side System, with maintained Objects
Cross-platform 2D game engine
Free MMORPG Engine. Develop and host graphical browser-based games.