I collect lawn gnomes. I just love the little bastards. Does anybody else collect something a little more off-the-wall than stamps, coins, and copies of Playboy?
I collect wooden slugs. Unfortunately, there are not so many of these in existence, so my collection currently numbers three. I’d love to have more, though.
I am also very fond of duck baskets. There are more of these than there are wooden slugs, but still not very many. I’ve got seven or eight ducks, and one reindeer.
I also have 150+ My Little Ponies, all of which got featured in the “What People Collect” exhibit at Crown Center (local mall kind of place). They usually live in a big plastic Rubbermaid box in my closet.
My mom collects playing cards. We’ve got 100+ different decks at our house. The more unusual, the better. Some are circular, some are square, some are “transformation” decks (each card is different. The best one is called “Keys to the Kingdom”), some have 5 suits, some are in other languages, and so on.
I collect dust.
I collect fat pencils from around the world. It’s easy to ask people to get them for me, inexpensive and easy to pack. I just got a gorgeous handcarved and painted one from Russia.
I collect my turds in little jars in the basement.
My father has a collection of dead but well-preserved bugs.
He also collects these carved and hand-painted things made in Mexico that are really hard to explain but really cool.
Are you looking at Oregon products? I see wooden slugs here now and then. Although it doesn’t sppear in the online catalogue, I just saw a myrtlewood slug at the Portland Made in Oregon store.
They may have come from this person.
I collect my cat’s whiskers. Hey, they look cool.
Check out this link: http://www.brunching.com/pornorpony.html
Tumbled stones… over 100… I absolutely love all the different colors
I’ve been collecting sugar wrappers–you know, the ones you get in restaurants, hotels, airplanes, etc.–in a scrapbook for many years now. Of course I remove the sugar first. I also collect salt, pepper and creamer wrappers.
I’ve got US Presidents, wrappers from many countries and airlines and hotels and states and many, many more.
At last count, I had 1,597.
I collect teapots. I especially like the Yi Xing ones from China. I don’t think that’s really weird, myself, but it’s not stamps, coins or Playboy.
I collect gargoyles. Not the horrible cartoon gargoyles from the TV show, but medieval-ish gargs. They started out small, mostly six or seven-inch high figurines, but each one I buy seems to get a bit larger than the others. The biggest one I have right now is a 15-inch winged-dog gargoyle made of concrete, but eventually I’ll have one about 4-5 foot tall made out of bronze. Normally that would be pretty difficult to find, for obvious reasons, but for a few years my dad has had a tenant in a renthouse who usually doesn’t have the money to pay the rent. She’s a wonderful artists, so we take sculpture instead of rent. She’s been working on the mold for awhile now between other projects. It ought to be pretty interesting.
I used to work with a woman who (as a kid) collected her scabs in a baby food jar. Geez, she was cool. 
I have a big jar on my desk at work where I keep all the staples I’ve pulled from documents since…oh, around 1996. Its about 1/2 full. I call it my staple collection.
A while ago, while showing this jar to a co-worker, I pointed to a staple buried in the pile and told her, “I pulled this one on April 18, 2000, right after I accepted this job.” Her eyes got really wide and she said, “How do you know which one it is?” 
Lamps in the shape of women. I’ve only got three, but they’re all excellent.
I collect etiquette books, especially antique ones from the turn of the century. They are a hoot to read! (Chapter 21: “Gracious Living Without Servants”)
My wife can’t believe that someone else does this, but to be fair, your collection sounds much larger than mine, which was active for only a year or so. I called mine a “used staple collection”.
I collect tarot cards.
Wood enema boxes, I have 11 of them.
Dragons. Ceramic, metal, plastic, whatever. Have quite a few, now.
Oh, and 25mm and 28mm miniature figurines. Been collecting those since I was a kid. Probably have a couple thousand of them…
Knives, daggers and shortswords. Science fiction books. Reference books. Chaos comics figurines. Software, (hey! I have the original windows 1.0!). Weird halloween decorations - I have a walking Thing and a skeleton as well as bouncing vampires.