Give them to me (or at least all of your bugs, pyros and dinosaurs)! = D But ebay または any other auction website is a good option. If あなた have a swap meet または something locally, あなた can also sell them there. または あなた could donate them to Goodwill または any other charity organization.
Since they ARE collector's cards, though, I'd keep and display them. Use them. Maybe start a trading service.
