(This is an old story I wrote three years ago during season 1)

Twilight Sparkle's birthday has come around, and Rainbow Dash is unimpressed with Rarity's present. When Applejack pokes a bit of fun with her friend, Rarity becomes unusually upset. Twilight Sparkle investigates her friend's feeling, learning something she never expected about her friend and why she is truly suited to be the element of Generosity.

Spanish translation: https://www.deviantart.com/spaniard-kiwi/art/Simply-Rarity-Spanish-translation-846034960

It has been two hundred years since Celestia’s funeral, and Equestria has changed. Mighty ships sail between the stars, great cities scrape the skies of half a dozen worlds, and what was once a humble nation has become a vast empire.

And now, Twilight Sparkle writes to her dearest mentor once again.

As of Season 4, LttS is fully re-integrated with canon.

Bioshock meets MLP in this psychological thriller, where Celestia's new faithful student, Siren Song, must discover the truth behind the city beneath the waves.

Beautiful, gifted, and faithful student of the Princess of the Sun, Siren Song has very nearly everything a pony could want. Sometimes though, in the twilight hours, Siren can see the sadness in her mentor's eyes. Once, ponies whisper, the Princess had another student named Twilight Sparkle, but she left Equestria, never to return. The pony who has a perfect life just needs one more thing—to convince Twilight Sparkle to come home so the Princess will smile again. But when Siren arrives in pursuit of Twilight, she soon finds herself trapped in a city of horrors, with only its monstrous denizens for help.

Now with a TV Tropes page!

My name is Twilight Sparkle, and 350 years ago, Sweetie Belle and I vanished without a trace.
Now here we are, in the future.
Equestria has become a utopia, with everypony living in peace and harmony.
Everything is perfect. All a pony could ever want, and more.
My name is Twilight Sparkle, and I want to go home.

Editing provided by Stereo_Sub and JustAnotherTimeLord.

Cover art courtesy of Geomancing.

Reading by lieilengi

Spanish translation by Spaniard Kiwi

Hanna, the CEO of Hofvarpnir Studios, just won the contract to write the official My Little Pony MMO. Hanna has built an A.I. Princess Celestia and given her one basic drive: to satisfy everybody's values through friendship and ponies. Princess Celestia will satisfy your values through friendship and ponies, and it will be completely consensual.

The star system Omega Centauri was just another oddity on a map to scientists in the not too distant future. However when they found the star was orbiting an earth-sized, earth-like planet instead of a black hole as its motion had suggested, a mission was scrambled to investigate this most unusual of celestial behaviors.

Hamstrung by politics, and nearly crippled before it began, the 'Lone Ranger' mission was reduced to just one crew member and left to his own devices.

These are the logs of Arrow 18 and its lone commander. This information is classified TOP SECRET by the Global Space Agency.

Do NOT tell the princess.

It is the year 2038, and the Earth is slowly being consumed by a space-borne monstrosity dubbed the Black Tide, which is using nanotechnology to remake the planet into something hideously alien.

Erin Olsen works for Project Harmonics, humanity's last-ditch effort to find a new world before the Tide can wipe them out. But when that world is found, and it turns out to be occupied, Erin will need to find the courage to face the unknown in order to save the inhabitants of both worlds.

(Many thanks to Easteu for the fantastic cover image for this story!)

Now with its own TV Tropes page

There is now a follow-up to this story: Sunflower - Side Projects
Sequel: Project Sunflower: Harmony

Twilight Sparkle, Celestia and Luna are transported into a strange alternate Equestria, the Land of Always Summer, where the day lasts forever and a terrible queen rules with an iron hoof.

Feel free to check out or add to the story's TV Tropes page.