I collect hockey (mostly Penguins and Sabres; some individual players outside of that), baseball (Phillies/Harper especially), and pro wrestling! (I'm PRETTY good about favoriting people who I want to PC, so look through that list if you're trying to put a trade together. My wantlist is not exhaustive!)
I also like relic cards a lot, even so-called "napkins". Even for players I'm not super passionate about! I just think game-used stuff is very cool.
Right now, a lot of my collection is fair game for trades. I only recently logged everything in and am still in the process of moving stuff I'd easily part with to my FT/FS list. PLEASE search my collection for teams and people you care about. If they don't line up with my own favorite people and teams, there's a very good chance I'm willing to move them. My FS/FT list is not exhaustive!