I used to travel a bit when I was kid and bottlecaps were one of the easier things to collect. So I've got a collection of bottlecaps somewhere with it's own collection of dust.

That's awesome. I would love to see a picture of your collection. I do the same with certain books. I have quite a few different copies of The Secret Garden, Huckleberry Finn, etc. I love the different illustations and book covers of each one. I have some that are vintage and some newer ones too.
I also collect pop up books, Disney snow globes, and dollhouse miniatures.
- - - Post Merge - - -
Oh, I also collect unique dolls. I recently got one called "Little Miss No Name". She's was made in 1965. I can't post a pic, but you can look her up. My husband says she's really creepy. I think she just looks sad.
Stone and glass plugs :3 This is my collection so far. The first row, to the left is all acrylic. The second row, in the middle is stone; in order from top to bottom they are purple agate, Tibetan agate (from Tibet), opalite, and blue tiger's eye. The third row is stone with one glass. In order, they are Chinese jade (from China lol), red goldstone (I sadly only have one now because my two cats like to steal and hide my jewelry for months at a time), blue goldstone, and the bottom one is glass (that pair is my favorite) And in case anyone was wondering what size these are, they're 19mm or 3/4 inch I like to collect tarot cards! I have quite a few decks, but I haven't bought one in a while because I have pretty much all of the decks I've ever wanted, and I kinda needed to take a break from spending! ^^;