This is by far the longest list of brand new feature ideas / enhancements that I’ve seen from a single person & it’s accompanied by beautiful designs! Amazing work.
My only criticism is that you’ve not acknowledged the reasons why Monzo haven’t built custom categories yet.
It’s one thing to design a user interface to manage them but as I’m sure you’d agree, it’s more important to rationalise the design decision first. You’ve explained why users would want this functionality but not why it would be a compromise by Monzo.
Custom timeframes tor the targets are also on their way.
Aside from that, there’s a lot of new ideas for Monzo users to consider requesting here 
And it’s great to see that Monzo’s work so far is inspiring such awesome projects from users!
Edit - it’s great to see that Jonas (one of Monzo’s co-founders & CTO) is a fan too!