GemRB is a portable open-source implementation of the Infinity Engine
Ze Text Adventure game Builder : Create as you play !
RTSish Game Engine
2D Game Engine
A fast, scalable, distributed game server engine/framework for C++
Real-time RPG for PC/tablet/phone; multiple quests and random dungeons
A space race game in the style of A Dark Room
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
Framework for a graphical point and click adventure game in Java
Cross-platform 2D game engine
A 3D multiplayer RPG based in the world of Khoras.
Free MMORPG Engine. Develop and host graphical browser-based games.