The Rayquaza card is a collectible because it's incredibly rare and valuable. It was first released in the Japanese version of the Pokémon Trading Card Game in 2004, and it quickly became a highly sought-after card due to its powerful attacks and artwork, making it one of the most iconic cards in the game. Today, the Rayquaza card is still considered one of the best cards to own and collect, and it is still highly sought after by many collectors. With so few of these cards available, it is no surprise that it is a collectible and highly desired item.