What horror movie does everyone need to see at least once?

Hey friends!! I’m trying to fill some gaps in my horror watchlist! I rather hear from y’all than google. lol
It doesn’t have to be the “best” just one that stuck. Maybe something not super mainstream!

Slashers, folk horror, slow burn, campy nonsense.. I LOVE THEM ALL! Let me know!

(I do first-time reactions on a small channel…but mostly I just want a good list.)