Collect movies, mostly focusing these days on 4Ks and Blu Ray releases but also DVDs and VHS from time to time. You'd be amazed what movies still don't even have a Blu Ray release or have one that is out of print and goes for like $200
The nice thing about 4K is it's region free so I have been purchasing a lot of movies from the UK lately. Not sure how many I have, but have 7 Ikea Billy bookshelves with 8 rows filled with movies plus many more shelves filled with movies.
Also collect hockey jerseys have about maybe 60-75 jerseys. Stopped collecting for a long time wasn't a fan of the Reebok jerseys but got back into it with the new Adidas ones.
Also sort of collect movie posters if I can find any good deals on them. My favorite one I own is my original Dark Knight one that was hanging in the theatre in Airdrie back in 2008 to promote the film.