I have seen so many people uploading texture pack that replaces the music disc with unused music from Minecraft - Volume Alpha and Volume Beta. But let's go further. This one replaces all the music discs to music from One, the soundtrack used in Minecraft: The Story of Mojang.

Here's all the current music discs and what are they now:

11 - Tsuki No Koibumi
13 - Cliffside Hinson
5 - Social Lego
blocks - Independent Accident
cat - Surface Pension
chirp - Danny Makes Chiptune
far - The First Million
mall - Certitudes
mellohi - Impostor Syndrome
otherside - Swarms
pigstep - One
stal - Buildup Errors
strad - I Glove Thy Flob
wait - Lost Cousins
ward - Fifflas