Good to hear that BK is enjoy Eleanor Steber's voice. I think it's one of the most uniquely beautiful ones ever. Mozart arias are perfect, but I don't think there are any pieces she did that weren't perfect for her.
Here's a discography, which may or may not be complete:
https://shrtm.nu/TftMThose 1950s Metropolitan Opera recordings on Columbia are golden --
Madama Butterfly and
Cosi fan tutte, both with Richard Tucker (and Roberta Peters in the latter), and
La fanciulla del West. I also see a
Marriage of Figaro with Ezio Pinza, conducted by Bruno Walter, that I hadn't known about. There are a number of live performance recordings that look very tempting.
In concert music she was especially known for Barber's
Knoxville "Summer of 1915", which she commissioned, and Berlioz's
Les nuits d'ete. I know she's on a
Porgy and Bess compilation. And good lord, look at that
Oklahoma!. I don't believe I've ever crossed paths with that one.
I am so happy to have known her and played for countless voice lessons with her at school. She didn't do much concertizing herself in those years, but I remember a wonderful
Four Last Songs with the student orchestra and Levine, another perfect piece for her intelligence and vocal beauty.