I am curious about this, too, from other metas. Speaking just for myself, I have not seen anyone use:
Inceptors - all other Primaris seems to get some use. Intercessors and Hellblasters are increasingly common. I've heard some people use Aggressors (particularly for Salamanders and Raven Guard) and I see them being built. Inceptors, the jump pack assault bolter Primaris, have yet to be fielded from what I've seen. Why this stands out to me is my Warhammer Store has 3 Inceptors painted and just sitting there for demo games and the manager is happy for us to borrow them and try them out (to encourage try & buy, etc.), but no one has. Considering they can accompany classic Space Marine Captain w/ jump packs, which are a common default HQ here, the lack of Inceptors is noticeable. Not saying they're competitive or not for their points, just noting their absence (Edit: I found they're slowly being added to Deathwatch for their special fall back rule).
Hunter/Stalker tanks - I don't see these very often, but that's not surprising. Partly, Dreadnoughts seem to have become the go-to Astartes Heavy Weapons vehicle platform here, so you don't need the Hunter or Stalker. Then in the case of the Stalker, an anti-air tank, Edit:
Flyers AIRCRAFT aren't as common or as threatening as in 7th ed (in fact, there are plenty of Flying things now). Thus, again they're kinda absent , but I can understand why (I now think it's time to re-think the Stalker tank).
Centurions - was pretty popular in 7th, now absent in 8th. Probably just seen as too expensive.
The meta has competitive and casual players, but so far (and it might change or someone may be fielding these that I haven't noticed), these aren't just rare but non-existent on the tabletop. That might change with a new Chapter Approved, etc.
Edited by N1SB, 20 July 2018 - 10:15 PM.