This

Lol, most likely.

I also have an autograph collection but they're mostly wrestlers I've met which falls under wrestling memorabilia

Valid, dnd... it's social, it's creative arts, etc.
Warhammer and other board games like carcazone or Scrabble, etc. are valid to me as well.
I guess it get complicated when it comes to cards. mtg and yugi and Pokemon, because it's also digital. Depends on consumption styles. Augmented reality playing Pokemon go?
Justin.tv or like "content creators" is fully their life. It's oddly uncategorizable. Just all on their own box.

MtG cards, coins and banknotes from all countries, champagne corks.

Dead things
Yu-Gi-Oh cards
Legos

I collect post count.

Finger nails and toe nails

nose hairs

Idk not much maybe so I'm stuff and stuff..

Maybe some items on crossout mobile to just have build options...

Collect bigsmokeharolds hair when he trims it