I think you should be able to customize whether it, and how often it, spawns from the Creeper loot table. I think I know how to make something like this, but I'm unsure if it'll be that good. Putting it here so others can know of this idea.

I would like to overhaul how you get custom music discs (drop rates + other non-creeper sources), but loot tables are complicated to generate automatically (and designing a nice UI to edit loot tables even more so). It might not happen for a while, but I would eventually like to offer more options for getting music discs.

Related to #18