The Rainbow Secret Rare design is extremely divisive, as the distinction can either catapult a card's value or leave it in obscurity, depending on the set's other designs
Another expensive card to cast, at 7 Mana, but because it has Haste and can attack immediately, it can claw back at least 4 Mana just by itself
This search isnt restricted to characters, items, songs, or anything in between
Some try to collect Master Sets (a complete set of cards including all promos and reverse holos) and so it can be effective to open a couple of booster boxes and then trade any doubles for cards you need and purchase the rest as singles
Fans who set themselves the goal of collecting one of every card in Scarlet & Violet151 cant ignore the Reverse Holo printings, so even Common cards like Pidgeotto end up being expensive if they have that foil sheen