You can't find "neocards" on Neopets. Neocards are a real-world collectible card game based on the Neopets universe. They were produced by Upper Deck in the early 2000s.
You can find information and pictures of neocards online, but you won't be able to find them in the Neopets website itself. You can look for them on sites like eBay, Amazon, or specialized online marketplaces for trading cards.