I’ve always been most into ledge, manual, and more technical skating but would say the most basic trick I can’t do is bs smiths on ledges, rails, or transition. I have done them a very small amount of times, but something about them makes zero sense to me and I can’t ever figure out why - despite putting in hours of sessions to try to get them. My dream is to one day be able to hold a well-dipped 10’ bs smith.
Also, pivot fakie on any size transition is crazy scary to me and I rarely do them.