Other bits of classical music in Astroboy: Night on the Bare Mountain by Modest Mussorgski in Robot Land (that's what is played each time Devil King makes an apparition), various parts of Swan Lake (including Spanish Dance when Astro and Elefun arrives on the island), and I think there's also a bit of The Sleeping Beauty, both of these from Tchaikovsky.
There's the very obvious "The Flight of the Bumble Bee" from Rimsky-Korsakov in, well, The Secret of Bee City.
I can't remember, but I guess there's someone's Romeo and Juliet version in Robio and Robiette?
I've always wondered what was the waltz Stanton (I can't remember the little robot name, Tom? Or was that the actor's name?

) danced with Uran's doll in The Robot Stuntman.
There are a lot more, I have always been interested in trying to list every classical piece in the 1980 series.
