A quick Google will take you to a number of lists. Some of the big Audiophile websites and YouTubers have listed their recommendations and some added playlists to streaming services.
I’d start with those and look to curate your own. As and when you hear a song/track that you think sounds great and demonstrates a certain attribute of your system, add it in. You are always better off with songs you are familiar with as that will help you measure new components. But don’t pick only songs that “sound amazing” as they might sound great on any gear. By this I mean there are songs that really push systems, speakers in particular. Try to look for those to add into the mix.
perhaps share your playlist once you have one. Enjoy the hunt.