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.
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
Artrage - A simple but lovely natural media painting and sketching program.
Invision - Prototyping and collaboration for design teams
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
Sketch - Professional digital design for Mac.