There's always Ella Fitzgerald, Ray Charles, Lena Horne and their friends. Always fun to listen to. Oh and Pearl Bailey. I loved her. Not just for her singing but she just seemed to be just the most joyous person.
The list of great singers is almost endless. All that you mentioned were on top of their game and well worth a listen, anytime.
I like Greg Allman on the "Laid Back" album. His voice is so mourful on three or four songs that I can't listen to it if I am sad. It will tear your heart out by the roots and hand it to you.