My fave would prolly have to be Buck O’Neil just bc of so much he did after he stopped playing/ Traveling around the country professing his love of the game for all that would lend an ear.
I loved Cool Papa Bell bc his name is just awesome and Satch said he was so fast he could turn out the lights and be in bed before it got dark! Or he would hit a ground ball up the middle and the ball would hit him sliding into 2nd base.
Josh Gibson of course too. As cheesy as it sounds, the old X-Files epi where Duchovny donned the Gibson jersey is what really got me interested in the subject.

I’ve since got to meet and sit next to a former Negro Leaguer, Carl Long, for an entire game. The stories were priceless.

Books? Dandy, Day, and the Devil is pretty good. The Soul of Baseball (Buck)
Sometimes the older info from these two books overlaps in my mind, but “Away Games” and “Clemente” are latin-focused but also talk about people like Dihigo and others who were quite dark and “kind of” broke the barrier before Jackie

I never actually read the book, but the classic movie The Bingo Long Traveling All-Stars & Motor Kings was based on a novel by William Brashler. Might be work checking out.

…is a good book re: negro league baseball and social/cultural function it filled.