I don't know if TV market is still a good proxy for whether a place is a good basesball market given the changes to how baseball is viewed, but here are the top 50 TV markets with what they have for baseball, AA and up.
1. New York - 2 MLB, 1 AA (EL)
2. Los Angeles - 2 MLB
3. Chicago - 2 MLB
4. Philadelphia - 1 MLB
5. Dallas-Ft. Worth - 1 MLB, 1 AA (TL)
6. San Francisco-Oakland-San Jose - 1 MLB (2 until 2025)
7. Boston - 1 MLB, 1 AAA (IL)
8. Atlanta - 1 MLB, 1 AAA (IL)
9. Washington, DC - 1 MLB, 1 AA (EL) (if we include Bowie)
10. Houston - 1 MLB, 1 AAA (PCL)
11. Detroit - 1 MLB
12. Phoenix - 1 MLB
13. Tampa-St. Petersburg - 1 MLB
14. Seattle-Tacoma - 1 MLB, 1 AAA (PCL)
15. Minneapolis-St. Paul - 1 MLB, 1 AAA (IL)
16. Miami-Ft.Lauderdale - 1 MLB
17. Cleveland-Akron - 1 MLB, 1 AA (EL)
18. Denver - 1 MLB
19. Orlando-Daytona Beach-Melbourne -
20. Sacramento-Stockton-Modesto - 1 AAA (PCL), temporarily 1 MLB
21. St. Louis - 1 MLB
22. Portland, OR -
23. Pittsburgh - 1 MLB
24. Charlotte, NC - 1 AAA (IL)
25. Indianapolis - 1 AAA (IL)
26. Baltimore - 1 MLB
27. Raleigh-Durham - 1 AAA (IL)
28. San Diego - 1 MLB
29. Nashville - 1 AAA (IL)
30. Hartford-New Haven - 1 AA (EL)
31. Kansas City - 1 MLB
32. Columbus, OH - 1 AAA (IL)
33. Salt Lake City - 1 AAA (PCL)
34. Cincinnati - 1 MLB
35. Milwaukee - 1 MLB
36. Greenville-Spartanburg-Asheville-Anderson -
37. San Antonio - 1 AA (TL)
38. West Palm Beach-Ft. Pierce -
39. Grand Rapids-Kalamazoo-Battle Creek -
40. Birmingham - 1 AA (SL)
41. Harrisburg-Lancaster-Lebanon-York - 1 AA (EL)
42. Las Vegas - 1 AAA (PCL)
43. Norfolk-Portsmouth-Newport News - 1 AAA (IL)
44. Albuquerque-Santa Fe - 1 AAA (PCL)
45. Oklahoma City - 1 AAA (PCL)
46. Greensboro-High Point-Winston-Salem -
47. Jacksonville, FL - 1 AAA (IL)
48. Memphis - 1 AAA (IL)
49. Austin - 1 AAA (PCL)
50. Louisville - 1 AAA (IL)
- No idea where Toronto, Montreal, Vancouver or any other Canadian market would be ranked if included above.