What are the rarest Pokémon cards?

The rarest Pokémon cards are the Pikachu Illustrator cards. Only four exist in the world, and one recently went for sale on eBay for $100,000.

Other rare Pokémon cards include the Numbers 1, 2 and 3 Trainer cards; the Pre-Release Raichu cards; and the Tropical Mega Battle 2001 cards. The rarity of the Numbers 1, 2 and 3 Trainer cards is due to one being released per year during the World Finals TCG. Publishers limit the Pre-Release Raichu cards to 10 to 15 cards worldwide, with an estimated value of over $10,000 per card. Publishers limit the Tropical Mega Battle 2001 cards to 12, so they sell for over $10,000.