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.
GIMP - GIMP is a multiplatform photo manipulation tool.
Corel Painter - Corel Painter is media painting software.
TwistedBrush Pro Studio - A powerful and unique natural media painting program.
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
Clip Studio Paint - The artist's software for drawing and painting.