Whatnot is particularly strong for graded Pokmon because its a live auction platform where collectors compete in real time, which often drives prices above standard listing platforms
You need all three to get all three promos
You can find a list of well documented errors here bulbapedia.bulbagarden.net/wiki/Error_cards 2 - become familiar with the card stock of pokemon cards
Scarlet & Violet sets added five new symbols: two black stars for Double Rare, two silver stars for Ultra Rare, one gold star for Illustration Rare, two gold stars for Special Illustration Rare, and three gold stars for Hyper Rare
Ancient Adamantoise Man, I absolutely love turtles, and they always have the most wild designs, like Fecund Greenshell, Ambling Stormshell, and Blossoming Tortoise