Twilight isn't having a very good day. An experimental spell blew up in her face, an army of changelings is attacking Canterlot, and she just died. Yet somehow, it looks like it's going to keep going downhill from here.

Given the chance to correct what's gone wrong, Twilight swears she's going to fix all this even if it kills her. Which it will. Frequently.

Cover art by Pixel Prism
Spanish Translation
Series TV Tropes page

This story is a sequel to Dusk and Dawn

The Dawn Militia and Nightmare Moon's armies continue to wage war across Equestria under the eternal night. The six bearers of the Elements of Harmony–Fluttershy, Rainbow Dash, Applejack, Rarity, Pinkie Pie, and Trixie–have been blessed with extraordinary powers, with which they lead the Dawn against the tyrant and her reluctant lieutenant, Eclipse.

But it's hardly easy. After all, what place does harmony have on the battlefield?

After discovering that Cadence is not who she appears to be, Twilight is sent to another world entirely by the disguised Changeling Queen to avoid her plan being disrupted.
When Twilight lands, she discovers that not only have Spike, Owlowiscious and Peewee followed her, but that they've arrived in a world where the main sentient species is human.
There's still a place where they teach magic, though.
Crossover with Harry Potter. Twilight will be effectively taking the role of Hermione.

I've marked this story as cancelled to reflect the unlikelihood of it continuing. If I do come back to it I'll revert that.

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

Professor Discord starts receiving unwanted attention from the new student of Celestial Academy, Twilight Sparkle. As Twilight spends her days trying to unravel the mystery surrounding the Draconequus, something watches from the shadows with malicious intent.

This is a story related to my other fanfic, "Are You Kidding?! There's PORN of Us?!" It's meant as a silly little side-story before I decide on what to do for an actual sequel.

Applejack and Rarity decide to host a dramatic reading of bad fanfiction written by Apple Bloom. How long will they last before it becomes too much?

What if the villains were allowed to win without a fight? Would all of their plans bear them the fruits they so desired?
Probably not, especially when their royal adviser is Twilight Sparkle.

A collection of (continuous) One-shots in which our heroes don't have any epic fights with villains, and simply allow the power of logic to crush all of the hopes and wishes of the would-be rulers of Equestria.

Currently up: Nightmare Moon, Discord, Chrysalis, Sombra (bonus chapter - the fight is so not-epic it happens off screen).

This story is a sequel to A Pony's Sympathy

Following Discord's last escape from stone [as seen in A Pony's Sympathy], Twilight Sparkle sought to understand his role in the keeping of Balance in Equestria

Her want to understand sparked an alliance of sorts, a kind of understanding between them. Although having one pony in his corner has done little to convince the rest.

His lack of empathy and understanding of a pony's sensibility has been tolerated by Celestia.

But while both the princesses and the bearers of the Elements of Harmony struggle with even more dire problems, Discord is forced into a lesson of his own, and it could not have come at a more inopportune time.

Continuing the story of A Pony's Sympathy, the fledgling friendship between the Spirit of Chaos and the Element of Magic may determine the fate of the ponies, and the way both sides of harmony regard one another.

[Written/published between Nov. 2012 and Nov. 2013, based loosely on Star Trek: The Next Generation episode 3x13 'Deja Q']

Twilight finds herself enthralled by Princess Luna and everything she represents. As Celestia's pride and joy, Twilight struggles to repress these feelings. But an old and well-known evil surfaces again at the worst time. Can Twilight fight off the spectres of the past?

Twilight wakes up and finds out that she's changed back into a filly! What kind of trouble will she get into? How will her friends react?