Porygon2 #138 from Scarlet & Violet Black Star Promos is a reverse holo promo card that currently sells for about $1.67 ungraded, with graded copies ranging from $7.50 at grade 9 to $100 at grade 10. A grade 10 copy sells for around $100, about 60× the $1.67 raw price, so high-grade copies are worth grading.