This is a fic based on the Time Loop Files, the format of which was first codified by Innortal on fanfiction.net.
Here's a brief guide.
The basic idea is, one character (the Anchor, usually the main character of a fictional setting) is looping back to the very first moments of their parent series every time either they die or some kind of time limit expires. They of course end up monumentally stir crazy given enough time.
Eventually others start to loop as well.
The reset is not always perfect. Sometimes a loop's history will be different to the "prime" loop, or canonical plot.
"Crossover" or "Fusion" loops also occur, randomly. These can involve the home loopers having a guest, or the anchor for one universe spending time in another, or replacements of one character by another.
Vacation Loops are where the Anchor (or others) decide/s "buck it" and lets off steam by doing whatever comes to mind. There's little or no attempt to maintain the original timeline.

In addition, and particularly more recently, it should be known that this story has a collaborative element to it - people may submit loop ideas or loops, ideally at the Spacebattles thread (a link to the current version of which is on the Trope page), and they may become included.

There's two page image options, thanks to Filraen - the current page image has been edited by the original creator from this work of theirs.. The other one is here:
http://hourglass-vectors.deviantart.com/art/MLP-Loops-466030169

In the far reaches of Canterlot Castle, high above in the towers lived the archmage. Everypony knew her, yet few had met her.

Twilight Sparkle sighed, having teleported away another noble seeking favors before reaching the top of the stairs for the second time today. They never learned. As the archmage, she already dealt with political squabbles far too often without inviting them into her home. Aside from personal favors for Celestia, she did what was required of her position and then returned to seclusion and research.

The nobility grumbled that no archmage should be a commoner, and Twilight’s disrespect toward them proved it. Each and every time they were forced to bow to her, they hated what they saw: the position, the status, the deference.

Was she not powerful? Was she not great?

Twilight, now reading through dusty scrolls and long forgotten tales, wrote in her notes — notes gathering dust of their own. A brief thought flashed through her mind.

Am I not powerful? Am I not great?

And then Twilight picked up The Tale of the Royal Pony Sisters.

Defunct side stories told in Across the Boundary. They can still provide a little context, but when in doubt, the main story here is canon.

Cover art provided by Lafiir

Princess Celestia, tired of the constant pressure that ruling a nation puts on her, decides to take a day off and let Luna take her responsibilities for a day, something the younger alicorn is more than happy to do. She disguises herself as a pink maned pegasus pony named Sunny Skies and decides to go walking around Canterlot without any supervision. Unfortunately for her, not all parts of Canterlot are as safe as the palace, and she finds herself at the wrong end of a gang of muggers, who decide to kidnap her for a ransom when they see how much money she has on her.

Luna freaks out.

Celestia thinks it's hilarious.

Find this story and more in a print copy! Just click these words here!

Featured on Equestria Daily 8/15/13

Go here for the French translation!

[img]http://i.imgur.com/CUBPvKI.png[/img]

Edited wonderfully by sqarishoctagon and Cloud Hop

Updated cover art by Dominatore

Twilight Sparkle wakes up one morning to a harsh dose of unreality. She is stranded, without her friends, on an island which matches no known locale on Equestria. Surrounded and harried on all sides by the alien and the dangerous, she will find her mettle sorely tested, and find perhaps that the best friends you will ever have in your life are the ones you make when your back is to the wall...

Thanks to CedricBale and noobie56xx for tracking down the name of the artist so I could give them credit.

After the War of the Ring and the return of peace to Middle-earth, Gandalf the White departs for Equestria to visit two old friends of his; specifically, a certain pair of alicorn sisters.

Yet he does not foresee that Equestria, like ponykind, has changed with the years since his previous visit, and so he is quite unprepared for what lies ahead. Can the Wizard endure the trials that this new journey will bring? Surely, but only if he makes a few more friends along the way.

Six more, to be exact.

Written with a heavily Tolkien-influenced style, which has been sampled by:

thefluffyone
LeJokstereerre
TheProfessor86

Countless thanks for your help, guys!

(Originally posted on 8/21/12 on FIMfiction. This is written by an author that has only seen the films and has yet to finish the books, so there may be slight discrepancies.)

Mort, also known as the Pale Pony (of Death), has been tasked to take time off from his rigorous duties of reaping souls. Seeking guidance, he is directed towards the town of Ponyville, to learn about the magic of friendship from Twilight Sparkle and her friends. All he needs to do is keep his true nature a secret. That shouldn't be too difficult...right?

Special thanks to Specter-Von-Baren and Pyrite Foolsgold for their help in proofreading and editing this story, as I really needed it. Additional thanks to Pilate, Chuckle5, Unimpressive Vagaries and Admiral Biscuit as well! Couldn't have done it without all their help!

Credit for the title card goes to Siansaar, AKA Carnifex.

For another excellent take on Mort, check out Sip's version!

Twilight Sparkle and Rainbow Dash awake to find themselves in a mysterious, compromising position. It's up to the brilliant mind of Twilight to deduce what series of events led them to this.

This story has sequels entitled Twilight Holmes: Sabotage After Sunset followed by Salting Snails.

Written for the Annual Twidash Contest.

Dramatic reading Part One and Part Two!

Let's Read blog by bookplayer here!

Remaster edited by Formerly Committed and Shellsh0cker.

This story is a sequel to Avocation

Life in Ponyville has been relatively quiet recently, which is somewhat surprising, given that the town's librarian tried to usurp the Equestrian throne only a few months ago. Aside from the appearance of a grumpy pegasus who set up shop as a cloudsmith, the aftermath is so unnoticeable that most ponies aren't even aware that the incident happened at all. Unfortunately, all that's about to change, thanks to the return of a certain revenge-obsessed showmare....

This is the fourth story in The Petriculture Cycle; reading the first three stories, which begin here, is highly recommended.

The artwork was provided by Page Turner, and the TV Tropes entry can be found here.