Also, if you are seeking more melodies / catchy tunes to model NES-MDB (https://github.com/chrisdonahue/nesmdb) might fit the bill. The modeling paper using that dataset + transformer XL - LakhNES (https://cseweb.ucsd.edu/~jmcauley/pdfs/ismir19.pdf) is a pretty nice paper, with interesting samples. I have been wondering what a diffusion based take on this data might sound like, and it might be a good fit if you are looking for stuff to try.