Xmind - Xmind is a brainstorming and mind mapping application.
ProProfs Knowledge Base - ProProfs Knowledge Base is a cutting-edge knowledge management software that assists businesses to reduces support tickets by self-help and create online manuals, guides, wikis, documentation, FAQs and more.
FreeMind - FreeMind is a premier free mind-mapping software written in Java.
Baklib - Make your knowledge base & help document online
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Solina Mind Mapping - Solina Mind Mapping is a smart mind mapping program and editor for capturing, refining, organizing and sharing the ideas with others.