kh1958 already listed a Billy Strayhorn piece, but there's an entire Strayhorn-Ellington-Johnny Hodges aggregate that's a special wing of Ellingtonia that's uniquely sad and beautiful. These reach the highest musical standards of all time and are never maudlin.
"Blood Count"
"Passion Flower"
"Ballad for the Very Tired and Very Sad Lotus Eaters"
"Isfahan"
...more!
And also related to Ellington, here is Abbey Lincoln's for-the-ages "Come Sunday"
https://www.youtube.com/watch?v=mAvN_ygGtdM