Asphyre is a cross-platform framework for Delphi and FreePascal.
IRB is a game creation toolkit
MMIM - Unlimited ideas for Mario Maker Levels!
Create symmetric sprites: browse, save to PC, or store online
AutoTeach makes kids study and learn in exchange for internet access.
Pear3DEngine is a modern and modular 3D development framework
Game framework on top of Python, Panda3D and Twisted