Flash Sentry has come to accept that in a world now full of magic, someone like him is nothing more than a side character despite how much they want to help. He's sent to live a life of boring mediocrity, until one unexpectedly strange day. From out of nowhere, a pod comes crashing down to earth. And inside is a device that will change Flash's life forever. The Omnitrix.

Written with the help of SuperSonicHeroes

Art by SlidDiamond3214

TVTropes

This story is a sequel to Bride of Discord

Discord and Fluttershy are blessed with a daughter named Screwball, who is gifted with incredible power that attracts the attention of the Queen of the Changelings...as well as her son.
When disaster strikes that tears Screwball's family apart, it is up to her to bring it together again.

New cover art by floppy-fluttercord

What if Discord had not been turned to stone by the Mane 6? What if he had escaped?
It is three years later and the Mane 6 have moved on with their lives, all except Fluttershy, who cannot get the draconequus out of her mind. The others are happy in their new and comfortable lives, until their enemy returns and will only relieve Equestria of his havoc in exchange for a bride.

This has been adapted into an audio series.

Also, here's a dramatic reading by Pablo Didonna, and one by 666HellGirl1

Cover Art by Nstone53

French: http://www.deviantart.com/art/Une-Mariee-pour-Discord-La-fuite-440318295
Spanish: https://www.fanfiction.net/s/10203187/1/La-Novia-de-Discord

*Bronyland Pony Awards Nominee 2013

A young antisocial teen receives a deck of Duel Monster cards and is thrust into an amazing adventure. How will he fair when the fate of the world rest on his shoulders.

Takes place in the Equestria Girls universe but is separate from canon events, so there are some differences from the movies. So remember that when you see something that wouldn't make sense in the movies.

Now on Tvtropes

This story is a sequel to Yugioh EQG

They thought getting to the finals was the hard part, but Flash and his friends will soon learn the the true competition will soon begin. Meanwhile, dark and mysterious forces are working to destroy everything they love. Can Flash fulfil his destiny or does our world's fate belong to the darkness?

Side Story
Now on TVtropes

This story is a sequel to Power Rangers: Guardians of Harmony

When a new enemy from another universe threatens their world, the Guardian Rangers must team up with another set of Rangers to save the day. Can they pull it off, or will our world be taken over by this mad man?

Over a thousand years ago, ten Elements of Harmony were lost in another world. Now a group of young teens must come together, to protect this world form the evil that threatens it. With the help of the mane seven, they must become the Guardian Power Rangers.

Takes place after Legend of Everfree and in place of the next film.

This story is a sequel to Power Rangers Guardians vs Power Rangers Revolution X

The Power Rangers are back! Now in their senior year of High School, the Rangers are hoping to have a peaceful time. But to their horror, a new threat has surfaced and is out to get them and take their Elements. To stop it, the Rangers must create new weapons, find new allies and defeat new foes. One thing's for sure, should they win, they will become legends.

This story is a sequel to Power Rangers: Legendary Guardians

Ten years ago, the Guardian Rangers fought to protect the legendary Guardian Elements from the many evils that coveted them. After that, peace came to their world and the rangers were able to move on with their lives. Until now.

A new evil has appeared and plans to destroy everything the Rangers have worked so hard to build and protect. In order to stop them, the Rangers must stand together. But that might prove impossible, with one of their own having joined the evil they now fight against.

Prepare yourself, for the ultimate battle between good and evil.

A dalek appears in Equestria - not just any dalek, but the one that had been corrupted by Rose Tyler's DNA. It has a choice of life as a pony, or dying, and finds that it cannot bear to die a second time. Thus begins a strange adventure as the dalek tries to find a place for itself in a world that is completely antithetical to its former existence and way of thinking...

...and why does that earth pony stallion look familiar...?