This is an uncredited list found on the internet. If anything it seems to leave out some artists, and suggest others that cannot yet be confirmed. Take it for what you will:
First season (1979): Billy Taylor, Barbara Carroll, Dick Hyman, John Lewis, Bobby Short, Teddy Wilson, Mary Lou Williams, Ellis Larkins, Bill Evans, Chick Corea, Tommy Flanagan, Dave McKenna and Joanne Brackeen.
Second season (1980): Eubie Blake, Hazel Scott, Cedar Walton, Hank Jones, George Shearing, Jay McShann, Roy Kral, Patti Bown, Duke Jordan, Oscar Peterson, Barry Harris, Sir Roland Hanna and Ramsey Lewis.
Third season (1981): Cy Coleman, Stanley Cowell, Johnny Guarnieri, Alice Coltrane, Jaki Byard, Dick Wellstood, Ray Bryant, Norma Teagarden, Roger Kellaway, John Bunch, Randy Weston, Jess Stacy and Jimmy Rowles.
Fourth season (1982): Dudley Moore, Marie Marcus, Joe Bushkin, McCoy Tyner, Steve Allen, Monty Alexander, Albert Dailey, Valerie Capers, Adam Makovicz, Dorothy Donegan, Derek Smith, Richie Beirach and Ross Tompkins.
Fifth season (1983): Dave Brubeck, Joyce Collins, Art Hodes, Richard Rodney Bennett, George Wein, Clare Fischer, Roger Williams, Joanne Grauer, Peter Nero, Steve Kuhn, Makoto Ozone, Dardanelle Hadley, Frank Kimbrough and James Williams.
Sixth season (1984): Dizzy Gillespie, Cleo Brown, Ahmad Jamal, Blossom Dearie, George Wallington, Shirley Horn, Kenny Barron, Dave Frishberg, Carmen McRae, Henry Mancini, Bill Dobbins, Walter Bishop Jr. and Paul Smith.