I had the best collection of Pokémon cards in my town when I was young and they were cool. Admittedly, most of them were directly or indirectly obtained via theft, but they were obtained nonetheless.

I eventually gave them away for free because years of Pokémon related thefts had left me crushed under the weight of my guilt, or something. I forget the actual reason. I could probably have sold that collection for hundreds of pounds, had I kept it.