Advancement: Knock Knocking

Description: Play through all the soundtracks of Minecraft.

What this means is that you have played every Minecraft music—from music discs, music from the menu and in-game background music.

I believe this is doable because it's just semi-RNG. A majority of the in-game background music can be played by simply putting yourself in a certain situation, like the aquatic track would play if you're near or in water, the Nether's track would play if you are in certain situations in the Nether and so on.

Also, the advancement name is a musical reference from Guns 'n' Roses' "Knocking on Heaven's Door". Just a nice touch there.