OpenToonz - OpenToonz is an animation program that is a free software version of Toonz, the animation software...
ibis Paint X - Drawn with + ibisPaint
Synfig Studio - Just another WordPress site
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.
Adobe Animate - Adobe Animate is a Flash, vector animation software.
Huion Sketch - Huion Sketch is an animation and drawing application that comes with all the tools and features, providing you ease when making a painting.