Once upon several different times, an entity of some sort came into one of many parallel worlds and made a soul out of a variety of potential somebody’s stars align. The result was the same across infinite possibilities: a song.

Twilight Sparkle and Spike take a break from the Box of Harmony to solve a far more dangerous puzzle.

Applejack and Rainbow Dash have an announcement for the Crusaders, in the form of sappy love songs.

Boast Busters, told from the Ursa Minor's viewpoint.

Four ponies getting ready to rock out (dialogue-only short).

Fluttershy has a secret crush weighing her down.