Hey, guys. I need a request a fanfic. It's a Pony on Earth fic where a lone pony protagonist is stranded on Earth (almost) taken over by aliens who invade Earth to harness magic from the planet's pocket dimension for their bidding, welfare and to prevent the natives from harnessing magic from Equestria somehow, and teams up with the human resistance to defeat the aliens in order to save both worlds from the brink of extinction.

If you find any, send me a link or a title of the story down below.

While not exactly what you're looking for, there's one story called Stardust by Arad that is close to your discription. Not sure how to put a link here when using a tablet.

7601042
Back and There Again?