Princess Celestia always knew that Twilight Sparkle was destined for great things, but she never revealed the source of that knowledge, not even to those closest to her. When the day of Twilight's true destiny finally arrives, can Celestia fulfill an ancient promise to save Equestia's past, present, and future, even it means saying goodbye to Twilight forever? How can Celestia refuse her mother's last wish?

Art by the inimitable Harwick

Humans.

Truth or myth? Ancient lost civilization or just an old pony's tale?

No pony has ever seen one, and most haven't even heard of them. But Lyra knows that these wonderful creatures are more than just old legends, and she's going to find out... and possibly drive her roommate insane in the process.

Sombra and Fluttershy are perfect for each other in every single conceivable way. He's a Dark Lord, and she's an adorable yellow pegasus who is the embodiment of goodness and purity. He loves Crystals and the enslavement of free ponies. She loves adorable critters.

They go on a wonderful vacation.

After months of practice, trial, error, and research, Twilight finally perfects the Wing Casting Spell. Her friends are more than excited to see the fruits of her labor. All her friends except for Rainbow. Why is the cyan mare so hesitant to congratulate Twilight?

Prior to Season 3.
Story seven in my Twidash Challenge: Slice of Life Theme
Cover Image by Psychodikdik

During a blissfully rare calm in the hectic storm of Ponyville life, a disturbance in the Everfree Forest goes undetected. After receiving a summons from the Princess, Twilight and her friends are led into a curious task, one that they find themselves ill-prepared to handle - managing their stallion double! As each of the girls meets their very own carbon-copy-colt, they learn that dealing with themselves can be much more frustrating than they first thought.

Annoyingly, irritatingly, intoxicatingly frustrating.

http://www.equestriadaily.com/2011/10/story-giving-love-helping-hoof.html

After the most important night of her career is ruined and its saboteurs not even so much as punished, Octavia's life changes. She begins to pursue a path that has never been seen before in Canterlot, where concertos and rhapsodies give way to controversy and rebellion.

A path where symphonies are composed with cans of spray paint.

Cover art used with permission by LuGiAdriel14

All of Equestria is united in celebration for the return of their beloved Princess Nightmare Moon. But when Celestia and everypony else recieve her she's skeletally starved, filthy, and very nearly dead. Meanwhile, while everypony's eye is turned, a lusty Blueblood pursues Twilight Sparkle, intent on adding her bloodline to his own so his family might step closer to godhood. (Alternate Universe, there never was a Princess Luna)

To commemorate the imprisoning of Discord one year ago, the first annual Celebration of Harmony is starting off with a grand party in Canterlot, something Twilight Sparkle has been looking forward to after many sleepless nights plagued by nightmares. After a chance glance at the party, Twilight and Princess Luna rekindle their friendship sparked on Nightmare Night. Meanwhile, Princess Celestia grows worried over the state of her kingdom, her sister disappearing at odd times, and the seal placed on Discord. Are the princess's worries well founded or is her sister's oddly secretive behavior taking a toll on her nerves? Twilight gets caught between the sun and moon as both royal ponies reveal that there is much that history has forgotten about the nature of the alicorns and even the draconequus.

AU for not taking into account Season 3 canon.

Amazing cover art by Sai, check the image source for more of his great work!