FreeMind - FreeMind is a premier free mind-mapping software written in Java.
XMind - XMind is a brainstorming and mind mapping application.
TheBrain - TheBrain: The Ultimate Digital Memory
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Mindomo - Easy-to-create and share mind maps, concept maps, task maps and outlines. Mind mapping software for Web, Desktop, iOS and Android. Mind map with us for free!
Coggle - Coggle is a simple, beautiful, powerful way of structuring information.