The changeling who impersonated Rarity during To Where and Back Again returns to Ponyville to say she's sorry.

A speedwriting exercise. Unedited.

A not so standard human-in-Equestria story including but not limited to: democracy, tequila, and robots.

Things escalate from there.

TV Tropes page

Now translated into Korean

What if Twilight had remembered a reforming spell? How would this decision affect Discord, Fluttershy, herself, and the whole of Equestria?

Cover art made by TheOperaticOne

Russian translation: https://ficbook.net/readfic/9144801

Day Four of #FluttercordWeek

Featured on 1/23/20, 1/24/20, 1/26/20,
1/27/20, 1/28/20, and 1/29/20

Luna has a secret.

A secret that she's kept close to her heart ever since her return from the moon, a secret she's hidden for so long that she's no longer even sure if it's real. At least until it returns to haunt her, and she has no choice but to confide in Celestia and hope her sister trusts that she hasn't gone mad.

It's time to tell Celestia about the circles.

Princess Twilight Sparkle discovers a centuries-old mystery hidden in the Royal Archives. Her investigation leads through layer after layer of deception and misdirection, setting her hooves on a path that seems to be leading to a mysterious secret. Along the way, she learns that some friendships can be very, very strange.

Book 1 of the Alicorn Adventure series.

AUDIOBOOK by VisualPony
Featured at the Royal Canterlot Library
TV Tropes Page (Courtesy of Sandtalon)
Goodreads Page (Courtesy of Facedeer)
Equestria Daily Page

WARNING: Major spoilers in the comments. Takes place several months after the end of season four. (Not a Da Vinci Code crossover, BTW!)

Do you see a dark tag? No, you don't. Not dark. Well, okay, there are a couple of dark-ish bits, but that's all. Not enough to warrant a tag. Speaking of tags, there really ought to be "Badass Twilight" and "Friendshipping" ones.

Sequels and side-stories (and more) can be found here Offprint and AO3, and a hardbound two-volume set of all that can be ordered from The Ministry of Image.

My editor for the first edition of this story was Gogito, and I can't thank him enough for all the hard work he did. My editor for the revised version was PresentPerfect, and he did a terrific job of getting the story into excellent shape.

It has been several years since Chrysalis’ defeat during the Canterlot invasion. Since then, the fortunes of her changelings and kingdom have rapidly declined. With mass starvation, ponies capturing more of her spies and love collectors every day, and her own powers diminished to the point of being a complete non-threat to her enemies, she fears that it may soon be over for both herself and her entire race.

As Chrysalis reminisces about past failures, a pony named Time Keeper crashes a large metal box into her bedchambers. He claims to not only be a time traveller but also to have accidentally killed Twilight Sparkle on the day she was supposed to go to Ponyville to defeat Nightmare Moon.

In an effort to avoid the prospect of the universe tearing itself apart at the seams from the ensuing paradox, Chrysalis agrees to go back in time and live out a facsimile of Twilight’s life herself, and if time allows, she'll work on her own little project: shaping the future more to her own liking.

Nightmare Moon had finally broken free of her prison. It was time to get her revenge on Celestia and bring about night eternal. Six mortal ponies rose up to stop her, using the power of the Elements of Harmony.

When the dust had cleared Nightmare Moon was gone, but so was Luna.

Be warned, there may be spoilers in the comments.