It's not really a mind mapping application but when I need to jot down some complex idea I use yED.
You can do all the normal things that flow chart tools can do but it has an amazing suite if auto arrange abilities that are highly customizable.
Site:
https://www.yworks.com/products/yed
Or kick the tires on the web version (less feature rich)
https://www.yworks.com/yed-live/