A not so standard human-in-Equestria story including but not limited to: democracy, tequila, and robots.

Things escalate from there.

TV Tropes page

Now translated into Korean

In times of old and new and now, we seek stories of greatness and wow. But what of the lessons we gained from tales of old? Will they withstand the test of time, be worth as much as gold?
An old dragon, wise and long-lived, sits in his cave, way up high; with a treasure reaching as far as the open sky.
Who shall claim it, and when, and where? And will it prove to be a prize most fair?
Time waits not for the champion to come by, so the dragon wonders, will his hoard with him die?

To save her sister and her faithful student, Celestia herself must travel into the ancient tunnels beneath the ruined castle in the Everfree Forest. She, and the guards who accompany her, must face the dark, twisting corridors. Still, what was Luna and Twilight's purpose at the old castle? Why were they unable to return of their own accord?

And what watches Celestia from beyond the light's edge?

Princess Celestia is the paragon of everything good and pure. Noble, fair and righteous. Beloved by all, and pillar of stability for Equestria since the time of Discord.

And currently not available.

My name is Frank, the new guy in charge of this body. I'm here to fulfill all your princess needs, until I find something better to do.

Human turned X fic. Post Season 3, but ignores season 4.

Cover art by Nun2artzy

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

Princess Celestia gave her life fighting against Sombra. That's the story everypony knows and tells and mourns every year. But Twilight is convinced she was transported to another dimension, and she won't let anything stop her from bringing the sun home.

Original idea by Rated Ponystar.

(A PoE story.) Additional Tags: (Slice Of Life)
All Twilight wanted was to give Spike a special gift for his birthday. Yes, it was a book, but it was a very special book. An Enchanted Book like that Power Ponies comic they had recently experienced.
Things went wrong when Spike startled Twilight as she was working the spell for his (secret) gift. Needless to say, startling Twilight while she's in the middle of a spell can be a bad idea - as certain frogs can tell you.
Twilight has every reason to believe that she is now trapped in a closed reality bubble fabricated out of her own magic, with no way out. She's lost in some made-up universe reflecting some random story line.
Mike, of course, has a different opinion about the matter.

WARNING: Both Twilight and Mike love talking technical and explaining things to each other.

Twilight's World now has an audio reading by No One and Nobody. Listen HERE.

This most excellent cover art was provided by Void Heart