This story is a sequel to Stardust

Times are changing for Equestria as Twilight’s return brings with it news of people and cultures from beyond the peaceful world everypony knows. Aid and volunteers are freely offered to help the besieged humans of Earth because every Equestrian knows that’s what good friends do. Unfortunately, making friends can also have the unintended consequence of making enemies.

When the monsters besieging the humans strike at Equestria with a level of brutality not seen in over a thousand years, the cry for help is sent to all the kingdoms of the world. Honored allies step forth to fulfill ancient treaties and oaths. Enemies, old and new, bury their grievances. An alliance never before seen in Equestria will be created to combat the monsters from the void.

And because of these events, a grim but welcome sibling to the XCOM project is born.

(XCOM/FiM Crossover)
(Sequel to Stardust, which I recommend reading before starting this. Fortitude Amicitia and Broken aren't required reading but are supplemental to the storyline)
(Gore tag for blood and violence)
(Alternate Universe tag because of the divergence from canon that Stardust has caused)
(Uses elements of Season 4)
(Coverart produced by the amazing Carnelian!)
(Many thanks to Arzoo, BradTheBrony, Vandenbz and Setokaiva for prereading!)
(As of 03/07/2016, the prereading team consists of Arzoo, BradTheBrony, Noble Cause and Metallusionsismagic!)
(Complete with it's own TVTropes page as part of the Stardust continuity. Could use some updating!)
(Character tags will be added as chapters are added!)
(Featured 5/12/2014! Thanks folks!)
(Possible spoilers in the comments! BEWARE!)

This story is a sequel to Stardust

When Equestria’s newest member of royalty asks for aid to be offered to her friends from abroad, the best and the brightest volunteer to serve. Captain Steel Song of the Dusk Guard are immediately mobilized to help XCOM defend their world from the enemies that besiege them. However, their first joint operation with the humans takes a turn for the worse and they quickly find themselves fighting for their lives against the full force of the monsters that threaten Earth.

(Stardust/Dusk Guard crossover)
(Coverart provided by a friend of Viking ZX!)
(While familiarity with both stories isn’t required, it is recommended)
(Many thanks to Arzoo for pre-reading!)
(All screenshots can be found at XCOM.wikia.com)
(Featured on 3/13/2013. Thanks everyone!)
(Now has it's own section on TVTropes as part of the Stardust series!)

This story is a sequel to Stardust

Twilight has finally returned home from the harrowing challenge that Discord set upon her, and the residents of Ponyville and the Elements especially look forward to having their dear friend returned to them.

Twilight, however, has changed. Still suffering from her injuries, almost incapable of using magic and haunted by the memories of her time on Earth, she becomes increasingly withdrawn from those who were closest to her. Will her frustration at her current state and her friends inability to understand her experiences cost her what she valued most before Discord's bet?

(Sequel to Stardust, familiarity with this is recommended!)
(Proofread by Arzoo!)
(Coverart commission drawn by the amazing KairaAnix!)
(Crossover with XCOM: Enemy Within, though the crossover and human elements are minimal)
(Featured 4/28/2014, thanks folks!)

Isolated from her friends and taken prisoner in the middle of a war, Twilight must deal with the very real dangers of being percieved as an enemy as well as the nightmares of her arrival on 'Earth'. Can she overcome her own fears and the fears of her captors? Will the wayward unicorn's assistance be a boon or a curse to the 'humans?' Most importantly, will she ever find her way home?

"In short, it's a story of friendship and plasma rifles, with the emphasis on the friendship. The characters are well written, the XCOM setting is fleshed out very well, and the story is compelling. If you love XCOM, you'll love the story, but even if you've never heard of it, it's more than worth giving the first 3 chapters a read.

There's excellent action later on, but the real strength lies in the collision between the friendly and naive world of Twilight Sparkle and the desperate world of humans fighting a losing war for survival and willing to do anything to turn the tide."

--Arzoo

(XCOM/FiM crossover)
(Cover art commissioned by a friend and created by the magnificent FoxInShadow!)
(Original cover art by the amazing Carnelian can be viewed here!)
(Gore tag for blood and some violence)
(Many thanks to the studius OminousTen, Arzoo, xXFluttershyForeverXx and finally Setokaiva for giving my rambles a once-over)
(Now with it's own TV Tropes page! Get to tropin' folks!)

You remember Canterlot. You remember the taste of victory. Across a thousand years and a hundred lives, it was the greatest joy you had ever felt.

And then, in a flash of heat and unbearable light, it ended.

Now you are alone. The rest of your kind are dead or scattered, and you cannot hear their thoughts.

There is a void inside you. A gnawing, endless hunger you cannot escape. It is killing you.

You need love to survive, but there is none of that here. Not for you. You can only steal it from them, these ponies for whom we are hungry.

[My entry in and winner of the "Most Dangerous Game" contest."]

This story is a sequel to The Three Sisters: Extended Family

A story of The Three Sisters Universe

Families are like fudge — mostly sweet with a few nuts. ~ Unknown Author

Chrysalis' daughters are serving their community service in Ponyville. Nothing can go wrong. Right?

Unless they all have their own agenda, and surprises keep piling up, complicating matters further. But anything to broker peace between the Changeling Nation and Equestria... right?

Art by the incomparable Conicer!

Now with a TV Tropes page! Warning: Will Contain spoilers.

This story is a sequel to A Little Push

Everypony must be so jealous of him. His parents are both retired members of the illustrious Wonderbolts. His mother was the last bearer of the Element of Loyalty, the only pony in hundreds of years to perform a Sonic Rainboom, and a key party in saving Equestria at least a dozen times.

But there are two sides to fame. As Prism Bolt strives to become his own pony, he'll find that stepping out from the shadow of his mother is easier said than done.

Once again, all credit for OCs goes to the supremely talented Kilala97

Proofreading done by the one and only, Prak. An author who deserves much more recognition than he gets.

This story is a sequel to Accelerando

The ponies calling themselves the Bearers of the Elements of Harmony (along with the lowly Vinyl Scratch and Spike the Dragon) awaken from their long artificial dream. In truth, they are the most powerful ponies in the world of the far future. In this seemingly perfect world, the only problems plaguing ponykind are in their dreams, and that makes The Mistress of Dreams the de facto ruler of Equestria.

But all is not rosy in Ponyopolis, and the only way out of this growing nightmare is by sacrificing one of their own...

This story is a sequel to Secret Histories

“To the precious peace-loving ponies of Equestria:

Has your life lost meaning in a world without Princesses?

Have law and order in your quaint little village collapsed under an endless onslaught of monsters and brigands?

Do you need a hero? Do you dare to be a hero in these dark and uncertain times?

Fear not, little ponies, for if you are brave enough, there is something you can do: Travel to Hoofington and spend a night at the Inn of the Prancing Pony.

I guarantee if you do, your life will change...forever.”

This is a story set hundreds of years before "The Best of All Possible Worlds", yet it was written after and influenced by the events of "Parade Coverage" and "Secret Histories". It was co-written with Hope. The cover illustration is largely taken from part of the fan art "First Day", by Harwick.

The "Alternate Universe" tag is because this story explores a different way that the events following the banishment of Nightmare Moon could have unfolded. As for the "Human" tag...well, that will become clear later.

This story is a sequel to A Twilight Sparkle Story

The story of Twilight Sparkle and her harrowing journey to Fluttershy's cottage, as narrated by the extraordinarily clever and handsome Discord.