Every Gloom card we price, most valuable first. Prices are what copies actually sold for, updated daily.
The same Pokemon is also printed as Erika's Gloom, priced separately because the game treats them as different cards.
What a Gloom card is worth
The most valuable Gloom on this list is Gloom from Aquapolis at $65.34£49.18€57.54, and the 26 priced copies across 24 sets are worth $282£213€249 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.
Gloom is printed in Japanese as well: 29 cards across 22 sets, the most valuable of them Gloom (Master Ball Pattern) from Pokemon Card 151 at $15.95£12€14.05. Switch the list above to Japanese to read those, or to Both to rank the two catalogues against each other.
The highest PSA 10 on record for Gloom sold for $717.07£539.70€631.50. 1st Edition and reverse holo printings are priced separately from the standard card, because they do not trade at the same money. Rarities here include Illustration Rare.
If you are trying to identify which Gloom 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: Aquapolis, EX Unseen Forces, EX Hidden Legends.