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.
Xmind - Xmind is a brainstorming and mind mapping application.
Baklib - Make your knowledge base & help document online
Visual Understanding Environment - Visual Understanding Environment (VUE) is a mind-mapping and concept-mapping tool.
Solina Mind Mapping - Solina Mind Mapping is a smart mind mapping program and editor for capturing, refining, organizing and sharing the ideas with others.
FreeMind - FreeMind is a premier free mind-mapping software written in Java.