Mind maps of Advanced Mathematics and various branches thereof
Here is a mind map by Konrad Voelkel that I understand and which was quite helpful when I was going to revise for an exam in Complex Analysis.
And another that is beyond my head presently and probably way beyond this site too ;-)
is the following which appeared here.(I keep this as a souvenir of how much abstraction there is in mathematics! I hope you would, too.)
Although I do not know whether you call it a mind map or not, the Periodic Table of Finite Simple Groups was a recent brainchild of Ivan Andrus, described in more detail in his blog post.
In picture, here it is:
Although it is a bit messy, you may be interested in the following map:
If anyone knows who made it, please let me know!