Reg the initial topic aka Mal Waldron on Prestige , as leader I would rate "The Quest" as indispensable .... as sidemean obviously the Eric Dolphy/Booker Little Five Spot recordings (with Thad Jones "Olio" as "left fielder" choice) .....
Interesting thoughts .... to me Mal Waldron had a number of great sideman dates on Prestige/NewJazz .... other recordings/sessions from that period suffered from the "Prestige approach" (aka assembling musicians rather by coincidence) and I'm not sure whether a different pianist would have saved the day...