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.
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Affinity Photo - Affinity is the imaging and design suite for creative professionals exclusively for Mac.
Procreate - Procreate is the most powerful and intuitive digital illustration App available for iPad®.