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!)

"... at the forefront of our fandom’s writing scene ... Masterpiece." —PCaRG
"... really enjoyable ..." —City of Doors
"...worthy of high praise." —PaulAsaran
"Lots of wonderful world-building, great action, well-developed characters and an engaging story." —Hoopy McGee

Steel Song is a lot of things. Earth pony. Uncle. Professional bodyguard.

Retired.

So when he receives a mysterious package from Princess Luna a few weeks after the changeling invasion, he's understandably apprehensive. More-so when he presents himself before the Royal Diarchs to find that not only do they desire him to come out of retirement, but to take command of a most unusual position...

A position that may have more significance than any of them suspect. Because strange thefts are occurring on the Equestrian Railway, thefts that nopony can explain. Thefts that may have far more sinister intentions than their seemingly innocent nature may convey.

Intentions sinister enough to shift the balance of power in Equestria forever.

Book I of The Dusk Guard Saga.
Epic Fantasy
Has a collection of Side Stories as well, the first of which is here.
Now with a TV Tropes page!
"This is 100% Approved by Twilight's Library!"
Added to Twilight's Library 11/26/2013
Added to Canterlot's Finest 12/01/2013

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!)

Everything happens for a reason, even if you don't know what that reason really is. After some untold period of time, Cozy Glow awakens and finds herself freed from her imprisonment. Unsure of where she is, how long she's been gone, or how she escaped, there's one question that haunts her and demands an answer - why was she released...

Artwork by Rhorse

If you want to help support me, I have a Tip-Jar/Patreon HERE

This story is a sequel to The Dresden Fillies: False Masks

It's been a while since the girls have seen their good friend Harry Dresden. Discord escaped, Luna attended her first Nightmare Night, the Royal Wedding was crashed by hordes of changelings, and Pinkie Pie threw a statistically improbable number of parties. They tried inviting Dresden, but between his new job and new apprentice, he always claimed to be too busy. The solution was obvious; if he couldn't come to his friends, they needed to go visit him. Besides, they say Earth is lovely this time of year. What could go wrong?

This story is a sequel to The Dresden Fillies: Strange Friends

Almost a year has gone by for Harry Dresden since he left Equestria. He'd have written, but between saving his newly discovered brother and destroying a scourge of vampires he's been a little busy. Then out of the blue he receives a strange letter from Twilight asking him to return. With no cases at the moment he eagerly accepts, but his friends aren't the only ponies expecting him. There's been a lot of rumors since his last visit and some ponies aren't too keen on seeing him come back.

A sequel to The Dresden Fillies: Strange Friends.

I always wanted to go to Equestria. When I got the chance, I took the deal without reading the fine print. To my surprise, I didn't arrive there as a pony, or even as a human. It seems I get to view this world from a different perspective than what I've imagined.

My name is Echo. I am a Diamond Dog.

-Edited by the one, the only, Nathan Traveler!
-(Cover by Jovial_Shake of fimfiction.net)
-Now featured on Equestriadaily.com!

This story is a sequel to Bride of Discord

Discord and Fluttershy are blessed with a daughter named Screwball, who is gifted with incredible power that attracts the attention of the Queen of the Changelings...as well as her son.
When disaster strikes that tears Screwball's family apart, it is up to her to bring it together again.

New cover art by floppy-fluttercord

This story is a sequel to The Man With Two Names

For the past year, Jeremiah Walker has wandered Equestria in the company of Trixie Lulamoon, seeking atonement and passage back to his own world, unsure if he will ever find it.

For the past year, Loose Leaf has investigated the events surrounding the human’s disappearance. He releases a full report of that night’s riot, a story Ponyville isn’t quite ready to hear.

For the past year, Spike has built a fledgling movement in Ponyville, fighting for non-ponies’ rights to citizenship. The tales of prejudice in Loose Leaf’s report invigorates the campaign, but draws opposition to the growing cause.

Now that the report is circulating across Equestria and their cover blown, Walker and Trixie march onward to the newly emerged Crystal Empire, following the only lead he has back home. There he runs into the frantic Twilight Sparkle, the pony who urged along his departure from Ponyville, and now needs his help to save this kingdom. Alongside her is Spike, who recognizes the human is just the figure his movement needs.

When Fluttershy finds a human in her backyard trying to eat one of her chickens, she and a majority of the residents of Ponyville only want this dangerous creature as far away from their town as possible.

After a less than stellar first impression, Derpy Hooves and the human struggle to quell the rumors surrounding his diet, and convince the townsfolk that he's harmless.

Will the human be able to make himself meek enough to coexist? Or will he be driven out of town with torches and pitchforks?

Each chapter is told from the perspective of a different pony.