The feature Nostur has to restore followers from clients that deleted followers or incorrectly synced has been a life saver - don’t know or haven’t seen anything like that on Damus or Amethyst. 

Other small things, like editing a note on Nostur for a small duration of time, haven’t tested that one but saw the feature for it. Maybe that’s not possible on clients on Damus or Amethyst, and there’s things on Nostur that could use some things from Damus/Amethyst.