The things we create should stay in our heads.
Sometimes they don't.

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

SF (canon species only; no humans) Ponies were magically and genetically engineered to be the perfect servitor race. They are powerful, adaptable, intelligent and completely under the control of their creators. A laboratory accident frees one such pony from her mental chains, but how can one mare save herself and the rest of her kind if she doesn't even know she's a slave?
This is not the Equestria you know and these are not your little ponies... not yet, anyway.

Tags: Adventure, Diamond Dogs, Gryphons, NO HUMANS (did I mention that already?)
Other tags: historical, mind control, Clarke's 3rd Law, excessive use of high energy physics, before they were famous.
Detailed review by PaulAsaran.
Cover art by endrome , used with permission.
Russian translation (partial -- 'unofficially' completed in the comments)
A Soot-Covered World, book 1.

First contact. Not just with a new world, but with a world in a whole new universe. Initial negotiations go well, so Princess Celestia makes a visit to this 'Earth' to cement peaceful relations. Unfortunately, even when you are as experienced as the goddess of the sun, it's the little things that can trip you up.

Preread and edited by Noe Carrier. SPOILERS IN COMMENTS!
Russian translation: Все это скоро закончится, принцесса by Smikey

Rainbow Dash was just cruising through life, one cupcake at a time. However, after a freak encounter in the kitchens of Sugarcube Corner, the pegasus finds herself faced with something she's never encountered before: love.

However, this is not your average love story. For you see, the object of her affection isn't some handsome stallion with a windswept mane and gorgeous abs. No; her love is a sink.

Now, Rainbow must face the challenges that come with love, all while learning to deal with strange urges, teething children, and dresses.

This fic is also available in French and Italian! Thanks to Bro-Nie and FiMvisible, respectively, for their hard work.

A big thanks to Golden Vision and Pav Feira, my editors! This fic would be even worse without them!

The Cutie Mark Crusaders try to follow the example of self-styled survival expert 'Bobcat Griddles' in a new quest to earn their cutie marks. What could possibly go wrong?

Twilight Sparkle has been keeping Spike up at night with obsessive writing. One night, Spike's curiosity gets the best of him, and he discovers Twilight has been writing bad shipfiction about herself and her friends.

He decides to teach her a lesson she'll never forget.

Featured in The Royal Guard.

Now translated into French!

Very crazy Fanfics Anonymous Reading!

Endorsed by the Twilight Sparkle's Secret Shipfic Folder Tumblr!

Third place winner of Everfree Northwest's 2014 Iron Author Competition.

Edited by Prak and Horse Voice.

Luna and Celestia leave the safety of their home in the city of Jannah to seek out a prophecy of power and destiny far to the west, at the end of the world, that only Celestia remembers.

And Luna is sick of the whole business. It has been a long, long journey.

Twilight told her friends of her adventures in the Human world, but she didn't tell them everything. One dark secret haunts her still.

Hamburgers are delicious.

Rainbow Dash can't wait to start the awesome day she has planned for her and Applejack. She's so eager she's already parked herself right outside the Acres, bright and early.

But geeze, what's taking AJ so long?