The answer is Pokémon...cards, of course! If you're looking to build your collection with the Pokémon TCG: Pokémon GO expansion, you can do it in style with a Pokémon TCG: Pokémon GO Poké Ball Tin.
Each tin contains:
Three Pokémon TCG Pokémon GO booster packs
Two sticker sheets for you to add a little Pokémon flair wherever you want!