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

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On secret assignment from Princess Celestia herself, Twilight investigates a powerful magical artifact for clues to the mystery of Luna's transformation in the evil Nightmare Moon. Incautious use of the artifact sends Twilight hurtling back in time. Can Twilight discover what caused Luna's transformation? And will she ever make it home again?

Kickass cover art used with permission from Bitz.
http://allthebitz.tumblr.com/

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.

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.

Twilight wakes up with a serious head-ache caused by her horn spontaneously growing due to a sudden increase in her magical power. Nopony seems to have an answer for it, but it has attracted the attention of an unusually powerful militant foreign nation intent on her capture and execution. When a string of events lands Twilight before Celestia's father himself he tasks her and her newfound magic with tying up some loose ends he'd left behind long ago, ultimately connecting with this foreign nation's goals. With their powerful enemy baring down on Equestria, intent on taking it in a stranglehold, Twilight and her friends have little other choice than to travel the world and hunt for the rest of Celestia's family and end several thousands of years worth of feuding to prevent the war coming to Equestria before they themselves are caught.

Image Picture by Lostzilla of DeviantArt.
(find him yourselves)

Ech is a whiny bitch, but he helped edit a little I guess. (you too bats)

This story is a sequel to Upheaval: Breaking Point

Following the events of Breaking Point, Twilight Sparkle and her friends discover that Equestria's demise may not come from an enemy invasion, but from within. The Barrier Lands and the Heartland begin the slow and uneasy process of reuniting into a single Equestria, but this long-delayed joining is already in danger at its conception.

With Celestia's power in her grasp and her agents by her side, the wheels of Black Rose's plans for Equestria's future continue to turn. However, her brazen gamble has done more than just bring down a centuries-old barrier. Ancient powers begin to stir: the remnants of a dark period in Equestria's history, the immortal inhabitants of Celestia's homeworld, and a rising tide of darkness coming ever closer.

Equestria is a land of magic and harmony, a peaceful realm ruled by immortal and benevolent monarchs. At what cost is this possible?

Following the discovery of a strange and powerful device, Twilight Sparkle is whisked away to the edges of a land she thought she knew so well. Here, surrounded by ponies whose very existences have been kept secret, she must contend with vicious enemies, hostile allies, and the truth.

Chapters 1-16 edited by KiltedKey

After failing to stop Nightmare Moon in the ancient castle of the pony sisters, Twilight Sparkle is left with a scar that will permanently change the rest of her natural born life. As Twilight recovers from her ordeal, she finds that she is left with a difficult choice. Either live her life as a lie or sacrifice her innocence to protect the ones she loves. The path before her is set and she must now walk it alone. The sands of time continues ever onward, with everyone already trapped in its muddy depths. The sun will rise and the sun will fall. Waiting for its call, Death awaits for all.

Tags, rating, and characters can change.

Art created by:
http://cuteskitty.deviantart.com (top)
http://ventious.deviantart.com (bottom)

I just put the two together

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

Harry Dresden, Chicago's only professional wizard, accidentally travels to Equestria after being attacked in the Nevernever. Twilight is none too amused with their newest 'guest', but trouble is brewing. Somepony is planning something sinister and the mane six may need Dresden's help however little some of them want it.

Story Image by: Lynxgriffin
Cover arrangement by: Novel Idea