Most Valuable Standard Card
Of the Pokemon cards that have been mass-produced, the most valuable card is the Charizard from the original deck. It is the most popular card, and traders value it for its powerful stats. A first-edition card is valued at about $125.
The Most Valuable Overall Card
The most valuable card in the world is the "Pikachu Illustrator" card. Only six of these cards exist; they were given out as prizes for a contest run by CoroCoro magazine in Japan. They have been valued at about $20,000 for a single card.
The Rarest Card
Although it has not been valued, the single rarest card is known as the "Prerelease Raichu." The cards were released as a mistake by Wizards of the Coast, and after recalling them, the company spent a long time denying they existed. They have since acknowledged the card, but only about four are still in existence.