This pack randomized literally every sound in the game, but does not change the pitch value of them. It also includes some of the unused sounds like ghast affectionate scream and cat hiss. The music is not randomized and the file is not large.

The sound name activated is "ultimate_random", so you can use it in /playsound commands. You might hear things like elytra loop, guardian lazer, angry bee, or other sounds that repeat forever, but relogging or using "/stopsound @s" works.

Here is a video demonstrating some of the sounds randomized (I don't know why restricted mode hides it):