It's Instrumental time! The pony levels, they are completely random. Their genres are next to their titles.
1.) BRONYnumberTHRE3~What We Built (Instrumental) Ft. Fluttershy - House/Techno
2.) "Once!" - HeyLasFas - Electronic
3.) (MLP fan music) The DJ, the Piper, and the Cellist - Celtic Electro/Psygoth
4.) Baroque Nightmare (Evil Rarity's theme) - Rock