MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
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.
GIMP - GIMP is a multiplatform photo manipulation tool.
Clip Studio Paint - The artist's software for drawing and painting.