We all like popping a music disc into your jukebox and listening to cat, but what if this was more expandable?
Introducing music technology. You can have something like a jukebox that gives sound as output, and then you could lead it to speakers using a sound cable. You could also have delays, just like redstone, and other fun mechanics such as increasing or decreasing the volume. Using something like noteblocks, you could write your own music, and output it through a speaker. This composition mechanic would be quite simple though, functioning much like a beeper speaker on an old computer. In my opinion, these mechanics would really expand on the wasted potential music discs and music boxes has.