Rainbow Dash flies east.

A lovestruck knight in Equestria's early days, unconvinced of his own worthiness, decides that he must prove himself to the mare he loves. With Princess Cadence as his guide, he is put on a quest by the Crown to go forth and right wrongs and ease sorrows associated with latent Chaos, all while learning of the Elements of Harmony from the ponies' companion races.

The entire piece is written in iambic pentameter, with the exception of Luna's pronouncement of the quest in the first chapter, which is an English sonnet.

Side-story to Past Sins - Slowly, the wounds inflicted by Nightmare Moon's reign heal. Ponyville is being reconstructed, and the last refugees are leaving the castle. Nyx is with Twilight. Celestia and Luna rule Equestria and guide the sun and moon once more. Everything is as it should be.

But some things are never washed away. These are the things that remain to remind us of the past. They remind us of the good times we've had with friends and family. They never let us forget the mistakes we've made. Everyone has them. Twilight has them. Nyx has them.

And, on occasion, when you share your scars, your photos, and your trinkets with another, they just might share theirs in return.

After a mishap in a magic duel, the ponies are transported to the Team Fortress universe. They'll take the classes places while The Engineer tries to find a way to get them home.

Humans.

Truth or myth? Ancient lost civilization or just an old pony's tale?

No pony has ever seen one, and most haven't even heard of them. But Lyra knows that these wonderful creatures are more than just old legends, and she's going to find out... and possibly drive her roommate insane in the process.

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Dear Princess Celestia,

I'm sorry I haven't written in a while. Things seem to be falling through the cracks lately. Spike thinks I should go see the doctor, but...

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Time twists and loops, and it does not always play out again as it did before. In this eddy of time, one rainbow-maned pegasus has been cut out of the loop before she ever existed.

Finalist and judge's top choice in the Equestria Daily Nightmare Night contest.

Fluttershy has been plagued by nightmares, and Twilight wants to help her get rid of them. But when the bookish mare begins to pry into the depths of Fluttershy's unraveling psyche, she finds more questions than answers. What do her dreams mean? Why won't they stop haunting her? And why does the creature she keeps seeing inside them seem like more than just a simple night terror?

Energy out is equal to or less than energy in.  The universe obeys simple and unbending laws.  Magic is not an exception.  Where does it come from?  How are ponies able to utilize it while so many other creatures aren't?  What are Celestia and Luna?

Scootaloo has always idolized Rainbow Dash.  When Dash agreed to teach her, she was positively thrilled.  Unfortunately, accidents happen.  Rainbow Dash isn't good at dealing with the consequences of her actions.