Never get tired of seeing other people's collections of stuff. Why is it so satisfying?
I collect dinosaurs/prehistoric animals as well as some more obscure extant species.
Also natural history ephemera, especially stuff I find myself-shells, bones, feathers, and other bits, as long as it's legal to have.
Pokemon collecting is DEFINITELY a thing I'll be sucked into in the future. Don't know where you guys find all those figures but they're great.