Unhappy that her future as a member of the monarchy is denied by Celestia, Sunset Shimmer escapes through Starswirl's mirror into another world, planning to take it over to prove once and for all she was fit to rule. What she didn't expect—besides a species change—was to arrive in a world already conquered.

TvTropes Page (Just created! Needs Help!)

Art (Will contain spoilers)

Sunset Shimmer - Bloody Sunset

Spoilers Ch. 11+: Angel - Angel and Sunny
Spoilers Ch. 18+: Princess - Comic
Spoilers Ch. 121+: Alejandra Acevedo - Flying at the speed of death
Spoilers Ch. 161+: Apple Bloom - Bloom
Spoilers Ch. 180+: Food - Sunset's Party Dress
Spoilers Ch. 185+: Fugue - Fugue by Rametep
Spoilers Ch. 197+: Exhausted

(Art is always welcome!)

WARNING: CONTAINS SPOILERS FOR THE WHOLE STORY: TIMELINE

This story is a sequel to Reformation of the Hives

Even though the threat of the jungle queens and Grogar have been diminished, life often times does not get wrapped up in a neat little bow. More troubles present themselves large and small. Our only hope is we keep passing life's constant tests, even when it is the last thing we wish to do.

This story is a sequel to Back and There Again

Rarity has 'landed' safely in Equestria and she can finally see all her friends and family again. Aiden can finally meet all these good people he's heard so much about, and maybe try his hand at a bit of amateur diplomacy.

Unfortunately, they weren't the only ones to find a way to travel to Equus...

Events fifteen hundred years in the making will come to fruition as old enemies and allies vie to decide the fate of two worlds.

This story takes place before the events of Season 8.
Extra tags (since five character tags are the limit): Tempest Shadow, Changelings

This 'Earth' is so close, and yet so far from anything Twilight described on the other side of that mirror. How is Rarity going to get back to her home when she can't understand anyponybody? And didn't Twilight say she became human, and humans didn't use magic? Yet clearly some did... and that wasn't even counting all the devices that might as well have been magical, as far as Rarity was concerned.

Who knew one strange little gem could cause so many problems? They'd taken it from her after it'd brought her straight into a lab for study, but... If she ever found it again, she was definitely going to let Spike eat it. As soon as she got home. And by Celestia, she was going to get home!

...Will Rarity ever find her way home? Is the gem that brought her to Earth the key, and is there more to the factions maneuvering around her appearance?

To complicate matters, this is an Earth recovering from its first alien invasion (Rarity being technically the second, then). ...Or does that actually explain things? No, no it doesn't. But it will.

------------------------------------------------------
To go with the Teen rating (or rather to explain it) there is light profanity and violence. I don't believe either are at a level where the warning tags are needed, but I'll mention it at least.
There may be some darker, more explicit moments in flashbacks, but I'll save those for Interludes.