Free mind mapping (and related types) software - Wikit. I see regular inquiries on Twitter and in forums from people looking for free software to support visual thinking.
To provide answers, InformationTamers have put together 14 pages to help you find the one for your needs. These show the platform, a screen thumbnail and a link for more information in each case. We built this article using the most complete source for details of information mapping software on the Web: Mind-mapping.org. Hat tip to Vic Gee who put Mind-mapping.org together and kept it up to date for years.