According to the search results, the most rare Pokemon card is the Blastoise Commissioned Presentation Galaxy Star Hologram card. Only two of these cards were ever made by Wizards of the Coast in order to obtain the rights to produce the English version of the Pokemon TCG. While there are many other rare and expensive Pokemon cards, such as the Pikachu Illustrator card and the First Edition Shadowless Holographic Charizard, the Blastoise Commissioned Presentation Galaxy Star Hologram card is considered the rarest.