IcoFX - IcoFX is an all-in-one solution for icon creation, extraction and editing.
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.
RealWorld Icon Editor - Create Windows icons and Mac OS icons from images and 3D models in an integrated icon maker.
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
IconLover - Icon editor for Windows.
Clip Studio Paint - The artist's software for drawing and painting.