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.
OpenToonz - OpenToonz is an animation program that is a free software version of Toonz, the animation software...
Clip Studio Paint - The artist's software for drawing and painting.
Synfig Studio - Just another WordPress site
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Adobe Animate - Adobe Animate is a Flash, vector animation software.