TwistedBrush Pro Studio - A powerful and unique natural media painting program.
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.
Corel Painter - Corel Painter is media painting software.
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
Clip Studio Paint - The artist's software for drawing and painting.
Artrage - A simple but lovely natural media painting and sketching program.