One thing I feel like I haven't seen enough is medleys of MLP songs all combined together. I'm sure they're out there, but I haven't come across many... but fortunately, I have a new one to enjoy after today.
Coconeru wrote an original orchestral piece which includes a medley of various FiM songs combined into a dramatic march. It sounds like something out of a movie—it's quite epic, as a matter of fact.
Give the song a listen! As always, you can find Coconeru's other songs on his Youtube channel.