RenPy - Ren'Py is a free and cross-platform visual novel engine that helps you use words, pictures, and...
Scratch - Scratch is the programming language & online community where young people create stories, games, & animations.
Sottolio - sottolio is a game engine to make in a simple way visual novels for your internet browser.
Cyberix3D - Free online 3D Game Maker. Make your own 3D games online!
Visual Novel Engine - Create your own visual novels, no programming needed.
Castle Game Engine - An open-source 3D/2D game engine for ObjectPascal.