how to tell the rarity of pokemon cards Check Card Value and Appraise Your Collection All Pokemon Card Rarity Symbols
Description
If you were a winner, your winning Pokmon Snap in-game photograph was turned into an actual Pokmon card, so not only are these rare right off the bat as a result but only 20 of each was made

Card Bending This test can also minimally damage cards you may own, but another option to ensure a card is fake or not is to bend it over in half without adding too much pressure (like putting it between books)
When trying to spot them on a Pokmon card, it was always found at the bottom left corner of the artbox

Also check the backs as the quality of their backs is the best indicator
And some have multiple forms they can take