Pigment by ShapeFactory - A unique way to explore color using lighting and pigment
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
ColorMe - Visualize The CSS Color Function
MediBang Paint - The official site for MediBang Paint, the free digital painting and manga creation software. You can download the latest version of MediBang Paint here, and get news and tutorials.
ibis Paint X - Drawn with + ibisPaint
Artrage - A simple but lovely natural media painting and sketching program.