Not baseball. But I stopped at an antique shop in upstate New York once and was looking at some old track & field memorabilia. The guy at the front yelled back, "That's the 'Chariots of Fire' guy." Turned out it was British sprinter Harold Abrahams' stuff: an original photo album (with several track photos), two leather bags (one with his initials), some awards, cards, etc. Very cool. I think I paid around $600. Consigned it to an auction house in London and it sold for close to $8,500. We were kind of broke when I bought the stuff and I had to talk my wife into letting me put it on a credit card. She was glad I did. It was so cool to think that he likely took those bags with him to the 1924 Olympics.
Here's the link to the auction:
https://www.bonhams.com/auctions/196...?category=list