A curio is a strange or interesting collectible object. Your vintage Pez dispenser collection, for example, is a group of curios.
Something worth collecting, whether it's a rare coin or a strange 19th century photograph or a bizarre clown painting, is a curio. You might even have a special, tall cabinet with glass doors for protecting and displaying your curios — you can call this a curio cabinet. The word curio, first used in the mid-19th century, originally meant specifically a collectible item from "the Far East," and was a shortened form of curiosity.