Double cab on vert - Hawk was trying it in the 90s, but in some interview he said it probably was impossible. Don't want to see them more often, just once would be fine. (Jake Brown did 720 ollies over mega gaps though)
Also I would like to see a 540 flip on vert or mini. 540 ollies look cool, so a proper 540 flip probably too. (I've seen people doing them sliding the last 180, doesn't really count.)
Also I have never seen a frontside 540 ollie on a mini.
On street, long or crazy high wall rides, like JJ's insane bank carve:
Or this one by Daan:
Those just look so good.
Off topic, just rewatched some of JJ's part and (except here) he is so underrated, one of the GOATs for sure.