Visual Understanding Environment - Visual Understanding Environment (VUE) is a mind-mapping and concept-mapping tool.
Xmind - Xmind is a brainstorming and mind mapping application.
PMM - Personal Memory Manager - Personal Memory Manager helps you spin-off from the top: manage your own knowledge and ideas.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Flying Logic - Highly visual software for planning support used by strategists, process improvement specialists, teachers, and writers. Windows, Mac OS X, and Linux.
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.