On the subject of remixes, this Mashup of Winter Wrap Up and Miku's 'Torinoko City' is amazing. As the top comment puts it 'It is very addicting and strange. 'the melody doesn't seem 'easy' many times yet it just...works.'
Episode 4 of Doctor Whooves And Assistant takes place during the Winter Wrap Up. As such, there's an awesome version of the Winter Wrap Up song sung by Doctor Whooves and Ditzy Doo.
In some alternate reality where a more ruthless Rarity clawed her way to the top of the business world and rules her corrupt, industrialized empire with an iron hoof, Art of the Industry would be her Leitmotif.
This video blends a song from Doug Walker's "To Boldly Flee" movie with the Cutie Mark Crusaders song. Best of all? Doug Walker himself approved of this!
The Clanky Donkey 2000 from Interrobang Pie - a chiptune remix of Yankee Doodle Dandy (present in the credits of A Friend in Deed) like only Interrobang can do them.
This Spy Aria is every bit as priceless - complete in the linked video with its own TF 2 re-animation. Oh, Scout's mother... I'll be there very soo-oo-oo-oo-oo-oon.
Original Songs
So, there we were, the Bronies, minding our own business on Youtube one day, when out comes this guy we'd never heard of before, "Ponyphonic", who proceeds to blow our minds with a Villain Song for Nightmare Moon named "The Moon Rises". With its Ominous Latin Chanting and For Doom the Bell Tolls, it gives us one heck of a number for Luna's fall from grace.
And, now, after a 5-month hiatus, we have a sequel to the above. There are no words to describe precisely how amazing "Lullaby for a Princess" is. It basically takes everything that was good about "The Moon Rises" and brings it Up to Eleven, in addition to the song being more than twice as long. It is Celestia's tearful, sorrow-filled song about her failure to see the depth of her sister's depression, a lullaby for Luna as she is banished to the Moon; it really drives home the notion that the punishment for the sisters' disharmony was twofold: one was banished for a thousand years, while the other was left to forever lead a kingdom, separated from the only one who could possibly relate to her. This time the voice artist is female, Christina Larson.
Then, this cover of "The Moon Rises". Just....this. Listen, and enjoy.
This (also found here) is a good song for Nightmare Moon and Luna, due to the lack of words and the title it's hard to tell if it's leaning to one or the other.
This is a dubstep song called Luna's Fury. Given the choice voice clips and the emotion in the title, its probably about safe to assume this is about Nightmare Moon.
Also by Derpedety, is this. Haunting, melancholy, and beautiful.
This is the extended version of Renard's "Psychoshy." Yes, it sounds like boss battle music of the most epic kind.
Eurobeat Brony's SuperPonybeatseries, which Ingram himself has praised! These remixes are among the most popular in the fandom, and Eurobeat Brony even wrote original songs based on Princess Luna and Discord, which are both pretty awesome.
As well as "Loyalty", an amazing alternative rock collaboration between AcousticBrony and Mandopony.
And an earlier collab between the two, "I'll Fly Higher", a Scootaloo theme.
As scary as it is, a few dedicated fans have taken the Grimdark asBuck fanfic Cupcakes to heart, and gone so far as to begin making a musical version of it, including songs with fanvoices that sound remarkably like the real characters, such as this one.
Something Broke, a 20-minute progressive rock song about the fic, is just about as awesome as it sounds, regardless of whether or not you liked the fic. And if that weren't awesome enough, Tarby (the artist who created it) has revealed that it was only a demo track, and the final version will be the opener for a 14-track concept album he's working on.
The Dark Reprises of "Art of the Dress" and "Cupcakes"*
the song from "Call of the Cutie", that is
are especially chilling.
Pony Swag from Swagberg and Maros. Careful; it has a fair amount of swearing in it.
RainbowCrash88's Twilight Sparkle Stage Theme for the same game is epic as well, being mostly based on Derpy Hooves' equally awesome Twilight's Sonata, but also containing parts of "At the Gala" and the show's main theme song.
Despite the terrible news that the game was recently hit with a Cease & Desist by Hasbro, the Rainbow Dash and Fluttershy themes are just as awesome as the others.
No! All order is aberrant! Chaos is the true state of everything! For Discord!
By the mind that brought us the original Lunar Republic tune: Hydra Pulse.
Rainbow Factory is a seriousEar Worm, especially when the violins kick in. Definitely not good for someone who wants to forget about the fanfic of the same name it inspired, but other than that, it's worth a listen or two... or three.... or twenty.
Glaze is not the only one to make Nightmare Night-themed music - Acoustic Brony and Mando Pony have tried their hoof at it together, with great results.
Balloons In My Basket A song celebrating Pinkie's utter irreverence. The song uses voice samples and they're matched perfectly. Dare you to say this doesn't give make you at least grin.
The theme song of the Reharmonized Series, "We'll Make It Through (Elements Of Harmony" is even more awesome, by virtue of having the mane six and the two Sixth Rangers all singing together.
Fillies and Gentle-colts, somepony had the time and effort to make the EquestrianNationalAnthem. UNITE OUR HERD AS ONE GROUP STRONG!
She Am Sky. Regardless of the glaring assault and battery to grammar in the title, a fast-paced and somewhat ethereal song, fitting for dashing through the sky at breakneck speed...
The Fall. a sweet song about the falling scene in Secret of my Excess.
H8_Seed, or TheUlasht (whom you may know as the artist who created Neverending Strife above), has recently taken to creating songs about the mythical creatures of the Friendship Is Magic lore. Here is one about a race for your life against a Manticore. Here's another written from the point of view of the lethal Cockatrice!
Here's another one about a battle with a great Hydra. And of course, no bestiary of Equestria would be complete without the all-devouring Paraspite swarm...
The Derpinator is wacky enough to fit Derpy, but badass enough to be a battle theme.
My Cadence. Beautiful duet between Shining Armor and Cadence. The vocals nail the voices down perfectly.
Spoiled Rotten, theme of... guesswho. Starts out like a classical tune, and then the wicked techno starts seeping in, very emblematic of Diamond Tiara's pseudo-elegant demeanor which gives way to a nasty personality whenever she finds someone to bring down.
The Brony documentary recently made had this song, "Let's Go and Meet The Bronies". The animation was done by the same animator that did Picture Perfect Pony. John De Lancie HIMSELF sings the song, which is full of nods to the fandom!
A lesser known musician named DimRevery has been gaining ground by producing some very good instrumental pieces such as Sunset Stroll and God of Chaos.
This song is the perfect love note from Derpy to all of us—that it IS great to be different!
Aviators has some excellent music to rival Glaze and Living Tombstone in awesomeness:
One last thing that I've gotta prove, one final goodbye, before we meet our doom: Something happened to the peace that we all knew! This is my one last letter to you.
His Love is in Bloom remix featuring Yelling at Cats is a song that should be played at ALL THE RECEPTIONS!
SoGreatAndPowerful. His work's a bit nichey, but there's a reason there's an entire tribute album dedicated to him. Note that he tends to unlist most of his music shortly after uploading to Youtube - this playlist is very useful.
Someone created a parody of Owl City's "Fireflies" titled "Fluttershys", and it was kind of sweet. And then a girl with a very nice voice sang it, and it became incredibly sweet. And THEN, this music video was made. Congratulations, you now have diabetes.
It gets better. That girl with the nice voice? She made a version of the song with Hush Now, Quiet Now mixed in. It isn't quite as long, but it's still amazing to listen to.
This same girl also did a cover of another Brony's parody of the Mulan song "Make a Man Out of You".
A brony wrote a version of Jafar's Villain SongYou're Only Second Rate for Discord. The writing is pretty good and their singing is pretty good as well, they just need an instrumental version of the song to set it to and it'd be completely awesome!
Another group set it to music and made a music video with it. Not only is it much better with music, the video is quite well done.
Using the Gorillaz Feel Good Inc. to retell Rainbow Dash and Fluttershy's cutie mark story? Nah, it could never work!
What happens when you mix Kanye west and Trollestia? Epic pony rap that's what!
A fan wrote a version of Be Prepared from The Lion King. That's cool enough, but then someone actually put it to music and sung it! While not perfect, it's still undeniably good and the creator has stated an improved, animated version is on the way.