My cousin had cards worth thousands of dollars and his house burnt to the ground a few years ago. He was completely devastated. Lesson learned i guess for him.
I was never into collecting cards, i collected comic books that were rare when i was a kid and still have a few. Nothing worth that much, but in 20-30 years i bet.
I have several autographed baseballs, footballs, jerseys, bats, etc. I can't remember all of them, but off the top of my head, Barry Sanders, OJ Simpson, Earl Campbell, Ken Griffey jr, Roger Clemens, Sammy Sosa, Nolan Ryan, Jose Conseco, JJ Watt, Tom Brady, Warren Moon, etc. I have several more that i don't remember. They are all in a climate controlled storage unit. No idea what they are worth.
One of my uncles worked in merchandise marketing throughout the 80's up to the 10's. He gave me all these over the past 20 years because he doesn't have any sons. He still has hundreds in his collection.
At one point i had 3 Roger Clemens signed baseballs, but they aren't worth too much so i have given them away.