I collect other peoples’ ear wax. I keep them in a large, locked file, organized by gender, race, physical location (on earth), and attractiveness level of the donor.
No, not really. But I had myself going there for a minute.
I collect pens. Fountain pens for the most part, but I like any pen that has a balance of style, feel, and function.
I have a bad habit of collecting cameras too. It’s more a reluctance to get rid of the ones I have than it is an active collecting. But I do have mostly “significant” cameras that were landmarks in their time: Minox B & C (GREAT conversation starters!); Canon A-1; Canon G1; Nikon F4s; a couple of old Brownie cameras; two Kodak Instamatic cameras (fully operational, except that film is a PITA to find); and a variety of others.
I also collect unique, manufacturer-published car brochures (hard-bound usually) and posters, mostly related to Porsches, but I will pick up the occasional oddity. My coolest (well, I consider it one of the coolest) is a set of dealer parts catalogs (before computers and microfilm catalogs) for 1970-76 DeTomaso Panteras that I got when I worked for my dad at a local dealership a few years ago. They sold Panteras back in the day, and he was going to throw out the old catalogs. Lord only knows why they had held onto them for 20 years. Turns out, I got them just in time as there was a fire that destroyed the place not long after.