Some of the best stuff I´ve found

Mort Takes a Holiday The Pale Pony (of Death) faces his greatest challenge yet: free time. by AnonymousMaterials 166,617 words · 4,410 · 79
On a Cross and Arrow Twilight and her five friends are transported across dimensions to... Ponyville, Equestria? But not the same one they knew. by Conner Cogwork 86,362 words · 4,491 · 100
Applebloom: Transform and Roll Out! Applebloom has a secret. A secret so well hidden even she never knew it. But when the truth comes to light, how will she cope when the reality of her past comes crashing down? More importantly, how will she deal with her new enemies: The Decepticons? by Dusty the Royal Janitor 120,901 words · 1,100 · 36
A Voice Among the Strangers An unsuspecting girl finds herself in Equestria, thrust into a world she has no concept of. Unable to communicate with the inhabitants, how will she cope? by Tystarr 205,112 words · 2,764 · 69

Looking for good fanfiction is like digging through shit to find diamonds, but when you finally find those diamonds, those are some DAMN shiny diamonds.

A few more damn good stories

Vanishing Act It's been ten years since Rainbow Dash's father disappeared in a wild, fierce thunderstorm. When the same strange storm hits Ponyville, Rainbow Dash does as much as she can to try and stop it from happening again. But magic has a strange h by Axel IV 81,156 words · 1,132 · 28
Super Smash Brothers: Disharmony Twilight and her friends are whisked away to a strange tournament on the edge of time and space. Can they make new friends with the colorful characters there? Will they cope with the strange goings on and dark conspiracies that are revealed there? by Dusty the Royal Janitor 79,780 words · 502 · 15
My Little Heartbreak: Heartbroken Anthony didn't have it easy in love. Now he's a pony named HeartBreak. Find out how she'll cope. by Jet_Black1980 49,839 words · 903 · 58
A Cog in the Machine The Flim Flam brothers have a secret; a live secret that breathes fire. Please, listen to my tale. by ManlyDerp 217,623 words · 434 · 29
Exit Through Canterlot Octavia pursues a new path in life, a path where symphonies are composed with cans of spray paint. by TheBrianJ 137,539 words · 1,978 · 49