I have Scapple, made by the same peeps who make Scrivener (which I also have). Just in case you don't kow what it is:
https://www.youtube.com/watch?v=5W2RB7mHQ3U
This is useful for top-level plotting and does this very quickly.
However, I came across something called Idea Spinner:
https://www.youtube.com/watch?v=7Vw1hoWAqbI&t=18s
There's no trial version of Idea Spinner, though it's only $19.99 (about £15).
BUT
Do I really need it?
Could I do the same things in Scapple?
(BTW I'm muskndusk on youtube and make some disparaging comments beneath the Idea Spinner vid

)
I'm a bit of a writing-software-aholic
And I'm procrastinating when I should be nano planning!
What do you think?