Xmind - Xmind is a brainstorming and mind mapping application.
Sketchboard.io - Visual Remote Teamwork. Solve problems and create ideas on endless whiteboard with your teammates by sketching.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Limnu - Sketch, share and collaborate with your team
Viima - Viima is the simple, yet incredibly powerful Agile Innovation Platform that helps you go from ideas to innovations – at the speed and scale of a true innovator.
MultiDraw - Draw with others in real time.