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.
ibis Paint X - Drawn with + ibisPaint
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
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.
GIMP - GIMP is a multiplatform photo manipulation tool.