A few things, actually. In order of how active and/or pricey they can get, here goes...
If you can believe it, I like collecting little bits of "trinket" junk off the ground. I walk like, everywhere, so every now and then I'll find something I wanna take with me. Probably half of these were found in the parking lot of my workplace, heh.
The ones above the salvaged sidewalk junk? My Walmart used to have a vending machine for little doodads and what-not for some quarters. I liked getting these little plastic crystals. I could've just bought a bunch off Amazon or something, but it wouldn't be the same, would it? The luck of the draw made it special.
As for more serious collections? I may not be a dice goblin like my nephew, buuuut...
...what can I say, I like TTRPG miniatures. Sorry for the blurriness. These are thumbnails above, so you can click them for a closer view.
Many of them are from Reaper Miniatures, though I do have some from
Warlocks Wizards of the Coast and some Pathfinder ones. No idea where the non-painted color ones are from, other than my local game store. I kinda like picking up those more obscure ones.