Roberto Clemente – 1955 Topps
Roberto Clemente was a Pittsburgh Pirates outfielder who got inducted into the Hall of Fame. Sadly, he died in a tragic plane crash after he notched the 3,000th hit of his career. His incredible career and heartbreaking death led to an increased interest in memorabilia. In 2012, a mint 1954 Topps rookie card of his went for $432,690. Another card, graded 9, fetched $478,000 around 4 years later.
Roberto Clemente – 1955 Topps
Stan Musial – 1948 Bowman
The oldest card that is still relatively affordable would be the 1948 Bowman card of Stan Musial. The St. Louis Cardinals icon was immortalized by the set. It is not very likely that you will have one of these in your attic, but it is not entirely impossible. At any rate, it is certainly worth a look since you can sell one in good condition for more than $1,000.
Stan Musial – 1948 Bowman