Twilight becomes alicorn of the stars. This is sort of a problem, because Luna kind of already was alicorn of the stars. Oops!

TV Tropes

Luna has had enough of Celestia's games, and has found the perfect means of revenge. Using a long-forbidden spell, she transforms her sister into little more than a small filly, all so she could pull the greatest prank ever. Unfortunately, she soon learns that before you fool around with dangerous magic, you really need to read the fine print...

A sequel can be found here.

[Featured on EqD and FiM Fiction] It is that time again, the dreaded flu season. Not even Princess Celestia, the ruler of the sun and day, is safe from it. When Celestia contracts the flu, what pony could possibly nurse Celestia back to health? Why none other than her dear, loving sister of course! Enter Nurse Luna!

Between crazed guards, a palace staff desperate to please their rulers, and a crazed unicorn running around, no pony is safe from this madness.

This is 100% Approved by Twilight's Library.

Dante has been given a job to help his shop get into business. But what happens if something went wrong during his job and he winds up in Equestria. At the same time a hidden and ancient evil before Celestia's Parents were born, starts to seethe back into Equestria, How will Equestria handle this new evil, How will Equestria handle Dante, and how will Dante handle Equestria and its citizens? Read to find out.

It's been over 1000 years since the romance between Twilight Sparkle and Princess Celestia has ended. Now they can't stand the sight of one another. Luna cooks up a scheme that sends Celestia to the past in hopes she can win back Twilight's heart and ultimately change their future!
Twilestia/Cadence/Luna/

Princess Celestia asks Twilight Sparkle to accompany her on a picnic with plans to seduce her younger protege. Celestia X Twilight (nothing too crazy tho it's a T rating for gosh sakes) ;)

There is a world where humans were living their normal lives. That is till a blinding flash of light flashed over their world.The humans were now what some would call Pokemon. Although it was cool and amazing to some at first, it quickly turned into a bloody war as new found power was given to everyone. A certain group of friends, who always thought life would be simpler as Pokemon, got together as one of them, namely an Eevee by the name of Josh knew this conflict of war had to end. So him along with his friends set out to end this war and actually managed do so within a couple of months. Peace managed to be secured in this chaotic world and these friends were held as heroes for their way of being the peace warriors for the god of Pokemon Arceus.

Now that the friends have done what their god has asked of them, they return to their normal lives. Hanging with each other as much as they can, or going to their places of work. On one day however they were all on a day of hanging out, then a blinding flash of light evaporated them and they were transported to a world where Friendship is Magic.

Princess Celestia, ruler of Equestria, found a small child of another species in the Royal Gardens. After tense thinking, she decided to take the creature under her wing, becoming his guardian. This child, later named Onyx, will try to follow in the path of his adoptive mother. Will he be able to make her proud? Will being a unique creature affect how he’s treated or his personality?
A story of love and family between a mother and her son.

[img]http://i.imgur.com/EO39ot0.png[/img]

(Begins before season one)

edited by xIMPERSONATORx
cover art by Shinonigga

Trixie returns to Ponyville to confess her love to Twilight Sparkle, and ask the mare out on a date. However, cold hooves get the best of her, and she realises that she must make a good entrance to impress her. And what better way than to show her amazing talents by wrapping up winter all on her own?

"That’s it! The Great and Powerful Trixie certainly is a genius! This is so great! Twilight Sparkle is sure to fall for Trixie!”

A plot between two meddling immortals to find something to occupy their young charges time with sees Laharl, Overlord of the Netherworld stranded in Equestria. Twilight Sparkle is tasked with looking after the displaced demon while a way back home can be found for him.

Unbeknownst to either conspirator dark forces take note of the cheerful little planet inhabited by the peaceful equines, with their own designs for the colorful land.

(technically there are no actual humans since they're all demons or angels...but I threw the human tag on there to be safe)
I feel like a small disclaimer may be needed. I'm planning to take some pretty severe liberties with Equestria and many of the characters from the show, so now and again they may act a bit out of canon character. Just a heads up!