Godot Engine - Feature-packed 2D and 3D open source game engine.
Unity - The multiplatform game creation tools for everyone.
DragonRuby Game Toolkit - DragonRuby Game Toolkit is a commercial-grade, yet beginner-friendly, 2D game engine.
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!
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
DragonRuby Game Tookit - Tiny, fast and cross-platform, 2D game engine in Ruby.