Sequel: Left Behind: Sunny Disposition
Apparently it was scouted and is on EqD too

Nightmare Moon was meant to be released after a thousand years. A momentous occasion for her but terrifying for all the ponies on her day of freedom. She would get revenge on her sister and cover the world in darkness and shape everything to fit it.

That was the plan, at least. Instead, something went awry with the spell and she wasn't released when she was supposed to be. The mare-in-the-moon is brought into a world with stagnated technology, giant cities, and no sign of her sister or any of the other immortals. In fact, ponies don't seem terrified of her at all, and the stay within the core of her powers infused and changed the alicorn's body drastically.

The alicorn had no obstacles left! But...she was also a relic of the past. A past everyone seemed to have forgotten. A past she could no longer look upon.

Artwork by ElkaArt. Link in source.
Big thanks to Kryostase for helping spot errors I've missed.

This story is a sequel to Morning Rain

There is nothing quite so bright and lovely as a field of sunflowers in the high spring sun, and nothing so pure as tested love.

Written for Scampy.
Find the collected works for the SunFlower Saga here.

This story is a sequel to Stay With Me

It rains hard in Canterlot, and cold, but at five in the morning in the arms of another, the morning rain isn't so bad to listen to.

Written for Scampy.
Find the collected works for the SunFlower Saga here.

This story is a sequel to Promises To Keep

Wallflower left her home very good reason, and when that reason rears its head in the form of an unknowing acquaintance from her past crossing her path, they bring with them a revelation that shakes the foundations of Wallflower's new home, leaving her with a choice to make.

Written for, and with, Scampy.
Find the collected works for the SunFlower Saga here.
Featured on 08/19/2020

This story is a sequel to Love Deeply

It's been six months since Wallflower found herself on the doorstep of her girlfriend during a torrential downpour, and stayed the night. The night when things changed in the slow and sudden manner of the inexorable.

Now, faced with a choice, Wallflower finds herself lost.

Written for, and with, Scampy.
Featured on 08/16/2020
Find the collected works for the SunFlower Saga here.

One in the morning is a time when you visit the people you need the most. Sunset Shimmer is that to Wallflower Blush, as Wallflower is to Sunset.

It rains hard in Canterlot, and cold.

This was done over the space of about three hours of compulsive writing. After a twelve hour shift. Give it a little grace. Written for Scampy.
Cover art also by Scampy.
Featured on 08/15/2020 for some reason

Prequel to this story is First Day Of My Life
Find the collected works for the SunFlower Saga here.

This story is a sequel to First Day Of My Life

Wallflower Blush doesn't have a lot of ways to spend the evening after work, but more often than not she finds herself walking the streets of Canterlot just to pass the time.

Written for Scampy
Prequel to Love Deeply
Find the collected works for the SunFlower Saga here.
Featured 9/5/2020

This story is a sequel to First Day Of My Life

It's Christmas Eve and Sunset Shimmer is spending her very first Christmas with Wallflower Blush as her girlfriend, but no matter what she does, Sunset can't make money appear out of thin air, and as much as she wants to get Wallflower something nice, all she can do is hope that she'll be happy with something thoughtful.

Not a Jinglemas gift, but still written for Scampy.
A Happy Hearth's Warming to you.

A Sunflower Christmas Special set between First Day Of My Life and Something Vague.

This story is a sequel to Running Out Of Air

With the end of their High School days approaching, Sunset Shimmer is forced to face the fact that she has more feelings for Wallflower Blush than simple fondness and friendship. The prospect of asking Wallflower out, though, is a daunting one.

Meanwhile, Wallflower is faced with the loss of the one good thing she's found once the end of high school comes and everyone goes their separate ways.

Written for Scampy. Cover Art by the incredible Countess Rose. Find her Twitter @CountessMRose
This is a prequel to Love Deeply and its proceeding canon.
Find the collected works for the SunFlower Saga here.