Your question prompted me to compile a list from my LP spreadsheet of all the artists for whom I have at least 20 LP's (below). I'm not sure this completely represents my list of the greatest (IMHO) since there are another 250 names on the list of the 1700 Jazz LP's I own, most all of which I love, But some of my real favorites, of course, did turn up.
I agree with Frogman that Kirk is among the very best, as is Mingus and Dolphy, but then I could go on and on ...
Miles Davis 55, Charles Mingus 51,Art Farmer 42,John Coltrane 39, Dexter Gordon 35, Thelonious Monk 35, Sonny Rollins 30, Donald Byrd 29, Rahsaan Roland Kirk 29, Cannonball Adderley 28, Sonny Stitt 27, Eric Dolphy 25, Duke Ellington 25, Gene Ammons 22, Art Blakey 22, Yusef Lateef 22, Gerry Mulligan 22, Count Basie 21, Dizzy Gillespie 21, J.J.Johnson 21, Jackie McLean 21, Horace Silver 20.
(P.S. I won't get into the whole CD vs LP thing because with Tidal, I essentially have everything in)