Air de Ballet is a guide to 19th century piano repertoire for ballet class by Ethan Iverson, who used to be music director for Mark Morris’s dance company, among other things. The page is richly illustrated with scores, audio recordings and useful commentary. Although you can play all kinds of repertoire for class, the 19th century dance tradition (waltz, polka, mazurka) provides the workable rhythmic framework for exercises, even if your tunes come from Maroon 5 and Ariana Grande.
My favourite creative tip from this page is the idea of improvising Czerny-esque etudes over the chord sequences of jazz standards (listen to his recording of Ain’t Misbehavin’ for an example). I’m also beginning to read some of the other articles on Iverson’s site, such as Mixed Meter Mysterium, a brilliant article on Stravinsky. Well worth stopping a while and browsing!
I’ve added the Air de Ballet link to my Playing for ballet class: Links, books, suggestions page. If you have any more suggestions let me know, and I’ll add them.