Bronzong - XY21 cards.

What a Bronzong - XY21 card is worth

The most valuable Bronzong - XY21 on this list is Bronzong - XY21[Staff] from XY Promos at $47.74, and the 1 priced copies across 1 sets are worth $48 together. Most of that sits in a handful of printings: the older the set and the scarcer the print run, the wider the gap to the rest.

If you are trying to identify which Bronzong - XY21 you have, the set name is printed on the card and the collector number sits in the bottom corner. Open the card here and the page carries every printing of it, the graded prices, and whether grading the copy is worth the fee. Sets to start with: XY Promos.