Taiga - Project management platform for agile developers & designers
Xmind - Xmind is a brainstorming and mind mapping application.
TargetProcess - Agile Project Management Web Application
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Plan.io - Planio makes web based project management and team collaboration more efficient and fun. It is the perfect platform for your projects, team members and clients.
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.