miniPaint - Online graphics editing tool use HTML5 technologies like Canvas, Offline support, Drag and Drop.
Unity - The multiplatform game creation tools for everyone.
RealWorld Paint - RealWorld Paint is an free portable image/photo/animation editor.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Paint XP for Windows 7 - Standalone old MS Paint program that allows you to get your old XP Paint interface in Windows 7.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.