SmoothDraw - SmoothDraw is an easy natural painting and digital free-hand drawing software that can produce high...
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Autodesk SketchBook - SketchBook drawing and painting software provides designers, architects, and concept artists the tools to sketch ideas quickly and create beautiful illustrations.
SVGO - Tool for optimizing SVG files
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.
SVGminify.com - Removes superfluous information reducing the size of SVG files