Godot Engine - Feature-packed 2D and 3D open source game engine.
QICI Engine - Full-featured HTML5 game engine with visual interface for building games.
Unity - The multiplatform game creation tools for everyone.
Scroller Game Creator - Create your scroller shooter game
Cocos Creator - Cocos Creator is more than a efficient, lightweight, free, open-source, cross-platform graphics engine: it's also a platform to create 3D content in real time.
Flowlab - Flowlab is an online game creator. Make your own games to share with friends.