Yes, you read that right... 50 songs. Circuitfry and BMDoubbleBass, along with various other musicians in the fandom all collaborated on this massive pony music extravaganza. Quality levels and "how pony is this?" levels are a bit random at times, but seriously... 50 songs. If you don't find at least 5 you like, I'm not sure what to tell you.
Check the whole thing out here, and their intro video after the break!