Mewtwo-EX #XY107 from XY Black Star Promos is a reverse holo promo card that currently sells for about $10.00 ungraded, with graded copies ranging from $9.99 at grade 7 to $244 at grade 10. TCGrader's AI has graded 5 copies of Mewtwo-EX (XY Black Star Promos), averaging 8.4 overall. Only 20% scored 9 or higher, so genuinely mint copies of this card are scarce. A grade 10 copy sells for around $244, about 24× the $10.00 raw price, so high-grade copies are worth grading.