My collection of Bionicle sets is definitely my most prized collection of all, but there are a few other collections I've made in my life.
When I was a little kid, I was a big NASCAR fan, so I often made my parents buy me those small toy replicas of those racecars (only a few inches long). I remember frequently playing mock races with those toys, laying colored pencils on the living room rug to mark the walls of the track. I also liked crashing those cars together frequently, like the real crashes I would see in the real races. These days, even though I still have a slight interest in NASCAR, it's nowhere near as great as it was when I was a kid in the late '90s. As for that toy car collection, it's all stored in a large plastic box in my closet. I don't know the final count, but I have a feeling it would be more than a hundred (I happen to have a few repeats).
Another collection I enjoyed while it lasted were those 3d puzzles, which are basically sheets of foam with stickers on them, you assemble the surfaces like a regular puzzle, but then you fit the surfaces together to create a three-dimensional model. The first one I got was Titanic. I got many more, mostly miniatures at barely 100 pieces, but there were a few larger ones at hundreds of pieces. My favorites of all were the series of skyscrapers that were made to scale, including the Empire State Building and the Sears Tower. I've since lost track of many of them, but my favorites, including those skyscrapers, are stored in my closet.
This last one, I'm sure if I should call it a collection since it's basically just getting started. It's a new series of Lego sets called Architecture which is basically recreations of famous buildings out of Lego bricks. The current count of my collection of those sets is at 4, all of them skyscrapers that are at the smallest possible scale to be made out of Lego bricks.
Those are the ones I can remember at the moment. Just to be clear, the only collection I really care about are my Bionicle sets.