Elon Musk is one of the most famous and important humans to ever live. His cards from the Currency Series 1 go beyond this niche card collecting realm.
Aside from the #1 Bitcoin card, I believe the Elon Musk #28, #28A will be the most valuable cards in Series 1. As far as his Cold Foil in Series 2, still collectible, but not as valuable as his Series 1 cards.