Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
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.
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
Clip Studio Paint - The artist's software for drawing and painting.