RPG Maker - Make your own PC game with RPG Maker. Our easy to use tools are simple enough for a child, and powerful enough for a developer. Try it free today!
Kodu Game Lab - Kodu lets kids create games on the PC and XBox via a simple visual programming language.
Flowlab - Flowlab is an online game creator. Make your own games to share with friends.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
Godot Engine - Feature-packed 2D and 3D open source game engine.
QICI Engine - Full-featured HTML5 game engine with visual interface for building games.