The FDS had huge potential but I have yet to see a good song made with it. I've open a lot of FDS nfs to look for one and it's all pretty bad. One of the issue seemed to be (im speculating here) that composer knew that the channel wouldn't be available in US/EU version so they always made it something optional (low humm in Metroid, bells in Zelda, etc). Sometimes only the title screen was making use of it.
But agreed, huge potential there.
The full list of games: https://wiki.nesdev.com/w/index.php/List_of_games_with_expansion_audio#Nintendo_...
Please share if you find a kick-ass song in this list!
-Mat