There are some interesting additions today. One, Rationale, is for making argument maps, and another, Pocket FreeMind, that has potential. The author says he may later make it produce actual mind maps on pocket devices.
gjots2: a simple, free jotter and outline processor for Linux,
NeoMem: a free outliner that lets you define different classes of record.
Rationale: A graphical tool for expressing what the makers call “Argument maps”.
Pocket Freemind: A free outliner that uses the FreeMind file format and runs on Windows Mobile.
EDrawMax: A diagramming tool that can make mind and concept maps.