Well, when I was younger I used to collect playing cards - ranging from Pokemon to Yugioh. It was fun while it lasted, but it honestly was just a complete waste of time (much like making this post). So I eventually stopped collecting them, and ended up selling my whole collection.
Right now, I pretty much only collect business cards and money. It may seem kind of funny, but that's all my life really revolves around (besides Pokemon). I have a rather large binder of business cards, in which it is a very valuable tool that I have. It allows me to be in control no matter what situation is thrown at me.