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.
Xmind - Xmind is a brainstorming and mind mapping application.
MyPaint - MyPaint is a fast, distraction-free, and easy painting tool for digital artists.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
GIMP - GIMP is a multiplatform photo manipulation tool.
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.