MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
SmoothDraw - SmoothDraw is an easy natural painting and digital free-hand drawing software that can produce high...
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
Paint.NET - Paint.NET is a free image and photo editing software.
Corel Painter - Corel Painter is media painting software.
PaintTool SAI - Learn to draw in different ways.