MLP/Undertale crossover.
Not a PWNY-verse story.

Long ago, the Monsters and Humans fought a great war. The Monsters lost, and were sealed in the Underground. It would take the power of seven human souls to break the barrier that kept them imprisoned. They only had six. And so the Monsters waited and hoped, praying that another human would find their way to the Underground. Some thought the seventh soul would give their King the strength to break the barrier. Some dreamed of a human who would be their friend, and save them all...or had nightmares of one who would bring back the war.

...but nobody came.

...but somepony did.

Eons after the war, with no way to tell how much time had passed above, a tiny blue filly with wings and horn fell into the underground, calling for her Mama. None knew the poor creature's nature or origins...but her soul was powerful with magic, even more so than a human soul.

None can know what will come...of this little 'Woona'.

Cover art by Sanyo21

This story is a sequel to Dreams and Disasters

Rainbow Dash has a new problem.

It isn’t that her relationship with Twilight Sparkle has diminished in the year that they have been together, even despite Twilight’s new position as an Equestrian Princess. If anything, the past year has brought them closer together than before. As far as Rainbow Dash is concerned, her life is pretty much perfect. That is, until she notices that her colors are fading.

In a panic to discover what is happening to her, she stumbles headfirst into an ancient secret dating back to long before the formation of Equestria, with her family in the middle. With Twilight and her friends, both old and new, at her side, she will once again venture out into the wide world of Equus, not for love, but for answers. About her family, her heritage, and the theft of the oldest artifact known to pony kind: The Celestial Prism.

Takes place canonically shortly after the Season 3 finale and well before the Season 4 Premier

Set in Dashverse. Applejack is taking Twilight Sparkle, Rainbow Dash and Pinkie Pie out to Appleloosa to help with the Apple Family Reunion and so she can compete in the Appleloosa Rodeo! Amid the celebrations of the Reunion, the rodeo and the one year anniversary of the peace agreement with the buffalo, Applejack finds that her favorite cousin, Braeburn, has been involved in making changes--including bucking tradition instead of apples.

How she attempts to deal with this, and her friendly-rivalry with Rainbow Dash, will push Applejack to her limits.

After an argument with Rainbow Dash about the romance plot in the latest Daring Do issue, Twilight Sparkle constructs a machine that allows two ponies to enter a novel, in order to learn more about Rainbow's obsession with pairing Daring Do with her bookish sidekick Rosetta.

Soon, the two find themselves in a Daring Do adventure, with Rainbow taking the name part and Twilight playing Rosetta. As they deal with ancient jungle ruins, mythical artifacts and old adversaries, Twilight is starting to see the appeal of the pairing.

But after all, it is all just fiction, and what happens in a novel has little to do with the real world, right?

Written for the TwiDash Group's Abandoned Fic Challenge.

Rated Teen for some violence, some very tame makeouts, and a slightly inebriated pony.

The princesses gave their magic to Twilight to prevent Tirek from stealing it. As a result, they end up stuck in Tartarus.

Marvelous place, Tartarus. Really brings ponies together. The fact that things manage to go downhill here says a lot about the wonders of family and alicornhood.

Spanish translation by SPANIARD KIWI

Audio Drama by Espa_Roba_5 and Ajvasquezbrony28
Live reading by The Living Library
Live reading by Astro-Brony

Proofread by Octavia Harmony

This isn't where I belong. I left all this behind years ago, moved on with my life. But a mare from my past brought me back, and now she won't let me go. So I'm stuck here, trying to make the best of it with ponies that don't understand me, don't even like me. But when something moves in the darkness, and when things go wrong in the cold, dead night, they'll turn to me to try to set things right.

Why? Because once a police pony, always a police pony.
~~
This is a spin-off story to 'Why am I Pinkie Pie?!', and will contain spoilers for that story, but it's not necessary to read that story to understand this one.
Cover art by the talented Conicer
Need more Cinnamon Swirl? Merlos the Mad wrote a fanfic of this story!

There is now a side-story: A Hard Day's Nightmare Night

Rarity and Rainbow Dash aren't exactly close. After all, they're very different ponies with very little in common. Or so Rainbow Dash thought.

A trip to Canterlot reveals that Rarity isn't exactly the pony that Dash thinks she is.

3rd place winner of The Writeoff Association's December competition, "Behind Closed Doors"

Art by Yoka-the-Changeling, Edited by Exuno

Lyra thinks Discord is an idiot for not thinking to dodge when the Elements of Harmony were about to strike him. Discord thinks this is the perfect opportunity for a game.

Part of the Borderworld.

Now with audio reading by Dreamless Portal. Chinese and Spanish translations also available.

We all dreamed of the day when we would turn twenty-one, the day when we would finally be able to legally drink our first alcoholic beverage, and Claire was no exception. Now that she had finally come of age, she asks her coltfriend Illusion to take her out for her first drink. However neither she nor Illusion were prepared for the hilarity that would ensue.

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?