The Raihan card is a collectible because it is a limited edition card that was only available in Pokémon Sword and Shield. The card features the character Raihan, one of the game's Gym Leaders, and has unique artwork. It's become a sought-after item for fans of the game, who appreciate the card's rarity and its representation of a core game character. It is an interesting symbol of the game, and offers fans a special way to connect with it.