At least the most expensive card ever sold is a classic that has sold for huge amounts for decades. I couldn't believe when the Giannis rookie and Mike Trout rookie sold for millions!
The only even remotely valuable cards I have are a Griffey Rookie and a Shaq beam team rookie. Having the Griffey rookie made me a god as a kid! As it's Beckett value was the highest of any modern card at the time.
I haven't collected cards for decades, but I was a huge video game collector until recently. The same madness that exists in the card game has infected sealed video games as well. A sealed left bros (first print of Super Mario Bros 3) just sold for 150,000, and there are at *least* 5 other copies that I know of in other collectors hands. One of them being a higher grade than the one that sold. I personally own a opened but complete copy and didn't even think it was valuable at all until I saw that auction.