My grail card is the Mame Akimaru Art Academy card. During my search for this card, I ran into a couple people who shared some helpful info about the card and its original artist.
Pokemon Art Academy is an illustration contest where players could create original illustrations, and the winners were awarded 100 copies of their own illustration on a card. There are discussions that some Art Academy cards have more than 100 copies, but I won’t get into that here. You can read about it here if you wish.
Mame Akimaru is the illustrator for the Space Pikachu card shown above. She is a bit superstitious. She had supposedly given a few of her cards away on the basis that you were a collector and weren’t going to sell it. One of the cards she had traded, was eventually sold. After it had sold, she got ill and she believed it was due to the selling of the card. So now, she is no longer selling or giving any away from what I’ve heard.
There are a few copies that’ve been shared on social media platforms. I’m not sure how many are out there, but it’s definitely much less than 100