GemRB is a portable open-source implementation of the Infinity Engine
Action RPG that's easy to mod
Arianne is an engine to develop multiplayer online games like Stendhal
3D urban environment renderer : browser-app ; as well as a GTA clone
plugin-based RPG manager in C++ and Qt5
Built to be ease of use, with no programming knowledge, Multi-platform
A 2D Adventure Game & Engine
LAIR is a Sandbox Dungeon Crawling Game
Role Playing Game Engine
Cross-platform port of Arx Fatalis, a first-person role-playing game
Cross platform 2D game creation framework with Python bindings
A turn-based strategy game in the spirit of Tactics Ogre
A Dungeons & Dragons Miniature Game.