Playing cards are available in a wide variety of styles, as decks may be custom-produced for casinos and magicians (sometimes in the form of trick decks), made as promotional items, or intended as souvenirs, artistic works, educational tools, or branded accessories. Decks of cards or even single cards are also collected as a hobby or for monetary value. Cards may also be produced for trading card sets or collectible card games, which can comprise hundreds if not thousands of unique cards.