This story is a sequel to Equestrian Vacation

Harry's time in Equestria has given him a lot. New friends, new magic, and new problems were guaranteed. But now Harry must deal with his inevitable return to Earth. Harry knows Voldemort will try to return to power, and this time he's ready to fight back. He must uncover the secret to the Dark Lord's immortality, and find a way to stop him before it's too late.

ON HIATUS FOR A SPELL

*Don't be fooled by the huge dislike ratio-- just a bunch of toxic Karens and bullies being bad. Give the fic a chance*

-Two Kings of Fire and Ice have been at war for some time, and their constant feuding and firing is causing much suffering not just for them but the galaxy, but their respective children (Who are in love) seek help to stop their wicked fathers.

-Lightning is reunited with an old friend who survived from his home planet, but she is determined to win him away from Starfleet and his family altogether.

-Starfleet is facing more backlash from haters.

-Swift Star is struggling to receive promotion, as well as another potential romance with Lightning's old friend.

This story is a sequel to Cinematic Adventures: Ice Age

The Mane Six and Spike, along with the Young Six and the Cutie Mark Crusaders. return to Hogwarts School of Witchcraft and Wizardry for a second year of schooling. They will reunite once more with Harry Potter, Ron Weasley, and Hermione Granger for an epic and mysterious quest as the students of Hogwarts are being petrified. Many believe the answer to this mystery lies within a long dormant chamber hidden beneath Hogwarts known as the Chamber of Secrets.

Along the way, they shall reunite with many old faces, encounter many dangerous obstacles, and uncover many shocking secrets from both the Wizarding World and Equestria.

This is a fic based on the Time Loop Files, the format of which was first codified by Innortal on fanfiction.net.
Here's a brief guide.
The basic idea is, one character (the Anchor, usually the main character of a fictional setting) is looping back to the very first moments of their parent series every time either they die or some kind of time limit expires. They of course end up monumentally stir crazy given enough time.
Eventually others start to loop as well.
The reset is not always perfect. Sometimes a loop's history will be different to the "prime" loop, or canonical plot.
"Crossover" or "Fusion" loops also occur, randomly. These can involve the home loopers having a guest, or the anchor for one universe spending time in another, or replacements of one character by another.
Vacation Loops are where the Anchor (or others) decide/s "buck it" and lets off steam by doing whatever comes to mind. There's little or no attempt to maintain the original timeline.

In addition, and particularly more recently, it should be known that this story has a collaborative element to it - people may submit loop ideas or loops, ideally at the Spacebattles thread (a link to the current version of which is on the Trope page), and they may become included.

There's two page image options, thanks to Filraen - the current page image has been edited by the original creator from this work of theirs.. The other one is here:
http://hourglass-vectors.deviantart.com/art/MLP-Loops-466030169

Be Awed and Amazed by the tale of Sweetie Belle as she traverses the multiverse in search of her lost mentor and friend, Twilight Sparkle! Will she find her in post-apocalyptic Equestria? Or maybe in a strange world where everypony is the wrong gender? Or even where a Pony claims to be a human? Read as she journeys through very familiar worlds you might have read about... if you dare!

At this point in time all the main worlds to be visited have already been chosen. Thank you all for the suggestions, and I hope you enjoy the surprises!

Here's the official TSC:F Music Intro: The Sweetie Chronicles: Fragments

WDTP: S2/3-CE
You can also visit the TV Tropes Page which has spoilers!

A strange storm transports Equestria and the Crystal Empire to Earth, less than four days before Germany would have invaded Poland and World War II would have begun. Unfortunately, during negotiations with world leaders, an evil entity breaks free of its prison and causes the war, and Equestria is drawn into it. How will they survive this?

Takes place just under two months after the two opening episodes of Season 3. Events diverge from there.

Inspired by 'Summoning Equestria' by NicieLunar and 'Ponyville, USA' by Rox