Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Sculptris - Sculptris: Enter a world of digital art without barriers.
Microsoft Paint - Paint (formerly Paintbrush) is a simple, ultra-basic graphics painting program that is included...
ShapeShop - ShapeShop is an advanced and professional 3D design and modeling application that comes with an easy-to-use and user-friendly interface.
GIMP - GIMP is a multiplatform photo manipulation tool.