After a freak accident, Princess Celestia finds herself in a whole new universe. As she seeks a way home, she is captured by none other than Team Rocket.

Welp.

Now on TV Tropes.

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

You are an ancient god who dates back to the times before history was recorded. Along with your other brothers and sisters, you lived in a time of paradise and happiness. You lived in harmony and ruled over the mortals without a care in the world. Until war broke out. A war that would last for centuries and caused the near extinction of all life in Equestria. During a last ditch effort to defeat your enemy you receive a grievous wound to your already tired and withered out body, which caused your body to turn to stone. Where your body would repair itself and recover your lost energy. However it's been centuries since the war, the world and people you had once known and loved has faded into history along with your existence, but the world has gone too long without you and it's about time you return.

Need help with grammar, please comment if you see any mistakes. I'm sure there are a lot.
Anthro- ponies still have horns, wings, etc
Some chapters will be comment driven