Baseball Mogul 2023 includes more than 2.2 million lines of year-by-year statistics, including records from every level of the minor leagues, 55 different NCAA conferences, and 4 different summer leagues.
I've also added season stats and biographical data for more than 2,400 Negro League Players. You can't yet start a new game controlling a Negro League team, because I haven't yet assembled the necessary team rosters and schedules. However, you can add Negro League players to historical seasons from 1920-1948 by checking the relevant box in the Player Settings Dialog (on the League Menu):
For example, if you start a new game in 1927, the National League and American League teams will be filled with everyone who played for those teams in 1927 — and the Free Agent list will be populated with Negro League players.
As long as you keep this box checked (in Player Settings) Negro League players will be added to the league each year, in the season when they turn 18.