How about a duo by The Association?
Diva: "Along Comes Mary"
"Along Comes Mary" is a fun song, it's got a driving beat and the lyrics are inventive and surprising. This appearance on The Smothers Brothers is pretty cute.
"Cherish" is such a treasure. The bridge is a work of genius - - the section that starts with, "Oh I could say I need you / But then you'd realize that I want you." The way the vocal line parks itself on that one note while the harmonies swirl around it, it's just astonishing. And the key change at the end, and the background vocals with their Oos and Ohs and Ahs. LOVE IT.