1926 Exhibits Ramon "Mike" Herrera ⭐ 100 Year-Old Card
Cuban born, Ramon "Mike" Herrera was one of the first players to play in the Negro League and the AL/NL, which blurred the racial barrier lines that existed in baseball until 1947.
I've never seen another copy of this card for sale in the wild or on any sales platform.

1979 TCMA #281, Bob Wilson ⭐ MLB Pioneer
Bob Wilson played 3 years with the Newark Eagles in the Negro Leagues before signing with Brooklyn in 1950. He spent 8 seasons in the minors before finally playing in the only 3 games of his N.L. career, in 1958, with the Dodgers.
TCMA cards are magnificent and provided me with the only mainstream baseball card I have found of MLB Pioneer, Bob Wilson, in his Dodgers uniform albeit 11 years after he played in a game for the Dodgers. I have seen some card art fashioned with Bob Wilson's likeness.

2025 Topps Update #HL-63, Heavy Lumber ⭐ Josh Gibson, SSP
Josh Gibson is considered by many historians and former players to be baseball's “true Home Run King,” even though his feats came outside the A.L. and N.L.

Playing primarily in the Negro Leagues, Gibson was legendary for his prodigious power, with credible historical research crediting him with 800+ home runs across league play, exhibitions, and barnstorming games, often against top white and Black competition. Because Negro League statistics were incomplete and long excluded from official MLB records, his achievements went unrecognized for decades—but modern scholarship and MLB’s formal recognition of Negro League statistics have reinforced Gibson’s standing as one of the greatest power hitters in baseball history, regardless of league.

1954 Globe Printing, Blossom Dairy, Charleston Senators Sam Hairston ⭐ MLB Pioneer
I don't collect Minor League cards, per se.
However, I've been known to dive into that pool occasionally, especially when a card captures a scarce bit of hobby and baseball history.
Good luck finding a mainstream playing days card of Sam Hairston because none exist.
He has a couple minor league card issues and this is one of them.
Sam played both in the Negro Leagues and Major League Baseball, primarily as a catcher, briefly reaching the Chicago White Sox in 1951.
Hairston was a standout performer in the Negro Leagues during the 1940s, playing primarily for the Indianapolis Clowns and later the Birmingham Black Barons as a catcher and outfielder, and known for his power and defensive versatility.
He also laid the foundation for one of baseball’s most accomplished families, as the father of major leaguers Jerry, John, and Joey Hairston.