Personally I collect VHS, DVD, and Blu-Ray. I also JUST started getting 4K Blu-Rays, I have a total of 1, lol (Predator 2018). And I somehow ended up with a couple CED movies, though have no player for them; ever heard of those? Cinema Massacre did a review video on it, interesting stuff.
I also want to get a laserdisc player, but not looking to spend a lot. Just hoping to get lucky and come across one at Goodwill or something. I really only want it to see the original A Nightmare on Elm Street Uncut, but once I got it I'd probably start collecting for it, too.
I focus on horror, sci-fi, fantasy, comic book movies, and animated stuff (though I'm not too heavy into Japanese anime). Also have a good amount of wrestling and Star Trek, because I'm such a nerd.
I also tend to sway more towards 70s through the 90s stuff, with a heavy focus on 80s stuff. Slashers, zombie movies, sci-fi epics, 80s barbarian movie, 80s "adult" animated movies (not porn, but stuff like Fire & Ice and Heavy Metal).