This is a Fallout Equestria (primarily) and Terminator crossover.

As the war between Equestria and the zebras pressed on, many members of the Ministries conceived of desperate strategies to end it through magical and technological creations of questionable nature. One of these was Project Infiltrator, a top secret project of the Ministry of Awesome. It's goal: to create a super spy that was the perfect blend of pony and machine. But just as its first subject was ready, the megaspells dropped, destroying Equestria and creating the Wasteland.

190 years later, Crystal Eclair awakens in a world of ruin and violence, completely clueless as to what happened to Equestria and herself. Her confusion grows into horror as she discovers that she is no longer a pony, but now a cybernetic zebra. With no other choice left, she sets out to find answers to her predicament. How will she handle the truth if she finds it? Will she find friends who can help her in a world that trusts no one? And what if those who have done this to her are still out there, eager for her to serve a new sinister purpose?

PS. This is not a Prequel to Broken Steel despite what a couple of websites that link back to this story say.

(Chapters 1 to 12 Edited by Alycorn~(CF), New Editor Double R Forrest. New description credit to Double R Forrest )

Hope is the faith of the young. Losing everything she holds dear, Puppysmiles embarks on the adventure of her life to find her mother, her hopes of meeting her again driving her through the horrors of a world not of her making. Too bad the Wastelands doesn't care about hope.

Inspired by the heroics of the mysterious mare known as the Stable Dweller, Silver Storm, a guard of the town of Marefort, decides to go on a daring mission to rescue her captured brother. Of course things rarely go as planned and her attempts at heroism drags her into a tangled web of plots and conspiracies as warring factions vie for control over the last great city: Dise.

Spanish Version translated by Spaniard-Kiwi: https://www.deviantart.com/spaniard-kiwi/art/Fallout-Ecuestria-Heroes-996263393

Changelings.

To most, they are the creatures that almost took Canterlot, shapeshifters able to feed on the emotions of those around them.
While this is true, it is not all there is to the story.

When the Great War began, an alliance was struck between Princesses Celestia and Luna, of Equestria, and Queen Chrysalis, of the Changelings.
The changelings, natural infiltrators since birth, would become spies for Equestria. In return, they would no longer be hunted, permitted to continue feeding as they had for countless years before their failed invasion, provided they not engage in acts harmful to the equine government or population at large.

Of course, that was simply the beginning. As the war began to escalate, Stable-Tec, the company responsible for the life-saving Stables, recieved a request from parties that would, as part of the contract, remain anonymous and unnamed.
They were asked to create something new, something that would allow both changelings and ponies to survive, and promote harmony between the races.

They were asked to create...

Project HIVE