The story is generally the same. A group of ponies go on a quest to stop an insane alicorn who had escaped banishment, learning about friendship along the way and mastering the Elements of Harmony. But the details...

It can be Trixie Lulamoon leading the Elements of Harmony against Corona.
Rainbow Dash could be Celestia's student and go to Ponyville.
Equestria could have a deep connection to three young people in its distant past.
The Elements of Harmony could have been moved to Manehattan for the ponies to quest for.
Princess Cadance might rule over an Equestria of music, with Octavia as her prized protege.
Or Spike and Twilight might have their roles reversed, the former a stallion and the Element of Magic.

And each one has been chosen by Discord, an Element removed to a seventh Equestria for purposes as yet unknown. Can they survive? Can they get home? Read and find out!

The Lunaverse was created by RainbowDoubleDash and is used with permission. Opening segment was written by Talon and Thorn.
The Hasbroverse was created by RK_Striker_JK_5 and is used with permission.
The Manehattanverse was created by Little Jackie Papercut and used with permission.
The Cadanceverse was created by GrassAndClouds2 and used with permission.
The Flipverse was created by Bed Head and used with permission.
The Dashverse was created by Trinary and used with permission.

And special thanks to dramatic_spoon for getting this all together.

This story is a sequel to Rainbooms and Royalty

Alternate Universe (Dashverse): A continuation of "Rainbooms and Royalty" Ponyville goes to sleep one night only to find in the morning that every foal in town is gone! The ancient evil King Sombra has returned and stolen foals from all over Equestria. But why? What is his true purpose in stealing them? It's up to Rainbow Dash and her friends to rescue the foals and stop this evil once and for all. But it's a long journey and complications arise with the ponies that join them. How can they save Equestria and preserve harmony when there is disharmony among their own ranks?

This story is a sequel to Hot Heads, Cold Hearts and Nerves of Steel

DASHVERSE: (Takes place several months after the events of http://www.fimfiction.net/story/68962/hot-heads-cold-hearts-and-nerves-of-steel)

Rainbow Dash and her friends are off to Canterlot to help in the preparations for the wedding of Princess Cadance and Shining Armor! But once she arrives, Rainbow learns of a sinister plot against Equestria. What's worse, she can't even rely on her friends to help her because one of them is not who she seems...

This story is a sequel to Rainbooms and Royalty

Dashverse: Rainbow Dash is geared up and prepared for the Best Young Flyers Competition in her hometown of Cloudsdale! And Rainbow is more than ready, having already used her Sonic Rainboom to help stop Nightmare Moon. When she and her friends arrive in Cloudsdale, things get even better: Rainbow has more fans than all the other competitors put together.

But that's when the problem starts. What's the cost of being the best? How can you have a competition when Rainbow is just that much better than everypony else? How will Rainbow Dash react to a horde of new fans? And how will her friends react to Rainbow's budding legend?

Taking place a month after the conclusion of "Rainbooms and Royalty," Rainbow Dash is settling into her new life in Ponyville. On the whole, it's great! But as some minor tensions crop up at her job and her new life, an old friend comes into town to turn everything upside down. What's a pony to do?

This is an idea that wouldn't leave my head, inspired by Fairy Slayer's "Mommy Nearest," Aldea Donder's "Alicorn," SoundofRainfall's "Play" and RainbowDoubleDash's "Lunaverse"

Alternate Universe: Instead of Twilight Sparkle, Princess Celestia made Rainbow Dash her personal student instead! Follow her through the events of the 1,000th Summer Sun Celebration. A reimagining of "Friendship is Magic"