Since 1998, Pokemon cards have been very popular in the United States. The hype died down a little during the early 2010s, but picked up again with the release of Pokemon GO!. Card collecting has boomed over the last two years, when lots of people started realizing how much they could make if they sell rare cards. The crazy increase in demand led to many stores enforcing a limit of how many boxes of Pokemon cards each customer could buy at a time.
If you were to get into Pokemon card collecting, I'd recommend doing it for nostalgic purposes over becoming a reseller. This is because cards can be expensive, with basic packs starting at about $10. Some people get lucky and find a rare or valuable card pretty soon after starting, but others never find one and spend hundreds of dollars on cards that they don't really care about. Sometimes used video game shops will buy and resell Pokemon cards for cheap, so if you're looking to complete your collection and want to avoid repeat cards, I would recommend checking with your local game shops.
Enough chitchat from me, let's take a look at some rare Pokemon cards! If you're interested in learning more about all the series of cards, check out this database.
The Illustrator is currently the most expensive Pokemon card in the world, with a recent sale reaching over $5 million. There are only 39 copies in existence.
The holographic, shadowless Charizard card from the first edition of Pokemon cards is one of most sought-after cards on the market. One of these cards in perfect condition can sell for over $200,000.
The Blastoise Presentation Galaxy Star Holographic card was created in 1999 as part of a presentation to convince Nintendo that Pokemon cards should be printed in English. There are only two that exist.
This Kangaskhan card was given to participants in a parent/child tournament in Japan in 1998. This card most recently sold for over $150,000.
This holographic Lugia card is a first generation print of the legendary bird. It recently sold for $144,000.
This trainer card was a promo card for a card game battle in 1999. There are only 12 copies in existence. The card recently sold for $65,000.