In every event, there are a million offshoots and effects, none really able to be fit into a normal narrative. Here is a collection of one-shots and mini-arcs spun out of The Elements of Harmony and the Savior of Worlds, so knowledge of that series will help immensely. Although I will do my best to make it as accessible as possible.

NOTE!:
All side-stories so far take place after the end of The Elements of Harmony and the Savior of Worlds.
The cast will be varied, as will be the stories, but all are canon.

Chapter One: A Picnic by the Lake: Celestia, Luna and Twilight entertain a guest who is more than meets the eye.
Chapter Two: Time Enough for All: The Doctor has spent nearly nine hundred years in Equestria, most it an extended vacation. But news of giants in Ponyville draw him out of semi-retirement.
Chapter Three: Contact Part One: Old Memories: Chip delivers the Princess' message to President Abernathy, which stirs old memories.
Chapter Four: Contact Part Two: Meetings and Greetings: Equestria makes formal contact with Earth, and an old mystery is finally put to rest.
Chapter Five: Family reunion Part One: The Best of intentions: Dinky sets out to reunite her father with his closest friends, roping her sister and the rest of the Cutie Mark Crusaders on a journey across time and space.
Chapter Six: Family Reunion Part Two: Memories: The TARDIS arrives at Earth, reuniting the Doctor with his past.
Chapter Seven: Shape up or Slaughter Out!: Shining Armor gets some help from an old warhorse to finish what he started with the Royal Guard.
Chapter Eight: How Christmas was Saved... Sort of: A short tale of how Santa Claus was saved one Christmas Or Megan had too much eggnog.

Trope page for The Elements of Harmony and the Savior of Worlds. Story listed there as well.

Equestria Daily page: A man can dream...

When a race of powerful ancient beings return to Equestria after an absence of thousands of years, it isn't to the sort of world they expected. Twilight Sparkle is now the first and last line of defense in a conflict that will decide the future of her planet.

Yes, there is life on other planets. This would be fascinating news to Twilight, had they come under more peaceful circumstances. Unfortunately, Thanks to Equestria's princesses, that life is angry and has come for its due.

Art by the fantastic Zutcha, as usual. Editing by Two Bit and Sparktail.

This story was written based on a simple idea from the HiE group forums. I haven't followed the idea exactly, but there's still a spoiler warning for those who want to check it out.

Sunset Shimmer has just graduated from Canterlot High School, and while that would normally be cause for celebration, it fills her only with a nameless dread as her friends begin to scatter to the winds to pursue their futures. With the latent magic of the human world contained and categorized and the Rainboom's idyllic days of schoolwork over, she finds herself without aim and listless, as though something important is missing from her life.

Fortunately for her, Princess Twilight Sparkle might know what ails her.
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So. First time posting on the site after a VERY long period of lurking and reading and enjoying the tales this fandom can produce. To my surprise, I found a dearth of a certain subset of story that I wanted to read, and so I have done this, to put my thoughts to words. After all, it is said that one should write the story they want to read, yes? I've been inspired by a variety of stories like it that came before, and I hope to equal their quality.

I'll try to update roughly once every couple of weeks; please be patient with me and I hope you give this tale a once-over. Pre-emptively tagging with AU, that I might diverge freely from what may come if needed.

Time after time, through chaos and through wars, Princess Celestia prevailed.

Of all the terrible forces she could have fallen to, Flim Flam Industry was the last one anypony had expected.

With thanks to gardrek for editing (3-6) and PinkieDP, Ice Star, and Odd_Sarge for prereading help.

Bómù Guāng Shǎn, the Prince of Friendship, asks Mèng Huàn, the Prince of the Night, for help investigating a mirror universe. The ponies there call it Equestria instead of Cōng Mǎ Guó, and it might have a few other differences, too...

The original, short story version came in 10th in the Writeoff Association's Feb. 2016 contest, "Look, I Can Explain." The cover artwork is by huhulin from Vectorstock, and overflowing thanks go out to M1Garand8 for help with the Mandarin names and the hànyǔ pīnyīn to render them in Latin characters.

The Great Freeze. Was it our hubris in controlling the sun, or was it that others started to covet that control? At this point, the whos and the whys don’t change anything. Our star is dying, and those responsible for it are long dead. Their causes and motives, lost to all but a few.

For the past hundred years, our sun has been growing dimmer, kept alive only by Celestia’s constant efforts. But not even she nor the legion of magi and scientists can stop the inevitable.

Our only choice is to flee to a new world, one that could give our doomed species a second chance. The Seeding colony ship is that chance. There are so many worth saving, and yet so very few seats.

May our children never forget the sacrifice of those we leave behind.

~Excerpt from Princess Twilight Sparkle’s journal three days before Seeding.

While this fic will borrow heavily from Beyond Earth, it will be written so that you do not have to know anything about BE to enjoy the story.

After the Friendship Games, Sunset feels it's time to return home.

Only when she gets there, Twilight's castle is nowhere to be found, Cadance just got her horn, and Princess Celestia is still calling the bacon-haired pony her prized student rather than a failed one. And just reliving her past isn't on the table thanks to a pair of wings Sunset seems to have sprouted upon her return to Equestria.

With Sunset being back before she's supposed to, will the world stay as harmonious and on track, or will everything go down in flames as Sunset has to deal with allegations that she's really a changeling in disguise, a nerdy stallion with blue hair that wants to be her coltfriend, a pretty pink princess in need of remedial magic lessons, and an annoying purple pre-teen pony that will absolutely not go to bed without first being read Starswirl's Complete Mystical Mysteries Compendium?

Only time will tell

Based on Crusaders of the Lost Mark

With all that glowy-magic stuff going on, one might have thought that the Cutie Mark Crusaders were going to become alicorns.

Well they did – without even getting their cutie marks.

This story is a sequel to Unwell

Twilight Sparkle is not well.

After the incident in Ponyville, Twilight has been moved to the Canterlot Mental Hospital, a top of the line care facility. Rainbow Dash has moved to Canterlot as well, to be there to provide support to Twilight.

Along the way, she will learn things about Twilight that she didn’t even know she didn’t know, as well as meet important ponies from Twilight’s past.

Twilight Sparkle is not well. But there is a plan for her and she is recovering.

The thing about life is, it never quite goes according to plan.

This story is a sequel to my other story, Unwell.
As a result, it won't much sense if you don't read that one first.

Cover art by dreamingnoctis. Check out his user page here.

This story is a sequel to The Mare of the Night

It's been six months since Starlight Nightflier, batpony prostitute, was hired to be the conversation partner of UN ambassador Daniel Habbuck. Since then, she's gained a new job, a new home, and a new future for her beloved son.

But that's not enough for Starlight. She wants to be more than just a friend to Daniel. Much more. But something's holding her back. Something from her past that refuses to die...

A collaboration between moi and Comrade_Pony

Special thanks to AidenHeaven, HolyStreak, KG472, zxzxzxzxzx24, and NarlepoaxIII for proofreading and editing!

Cover image source: Link