The Conversion Bureau never made any sense anyway, but here are some places where it would have made less sense.
Not necessarily worlds where the ponies would lose the fight - just worlds where conversion wouldn't logically work.

Before suggesting a World, read the index to make sure I haven't done it already.

The Lone Wanderer has been known as the man who shouldered the nightmares of every man, woman and child in the wasteland, so that they may live. But when the Wanderer was once again abducted by aliens, he found himself falling, quite literally, into a whole new wonderous world, untouched by the horrors of nuclear devastation.

He has been facing other people's nightmares constantly for almost a decade, it was high time he was allowed to wake up.

Meanwhile, the ponies of Equestria are baffled by a strange object that fell from the sky.

Fallout/FIM crossover. HiE. T for violence and some language.

Now with a TVTropes page!

Once, I was a simple human. I spent my days living my life and enjoying as the days slowly ticked past. I had a girlfriend who loved me and who I loved in return.

That all changed one day when I went to a costume party dressed up as the character Amaterasu from the game Okami.

Now I don't even know what I am anymore.

I have the powers of a god, but what am I supposed to use them for?

Edited and Proofread by Courage Fire and tytyvm starting from Fourth and Fifth Howl.

Legions bow before him! His name is whispered in terrified awe by even the greatest of clans and all know that none among the Horned Rat's children are as favoured as the magnificent Greyseer Thanquol (according to him, at least). His latest plan is ready to come to fruition and the stupid elf-things will face the unmatched might of the skaven horde, led by the equally unmatched genius of Thanquol of course.

Obviously the original plan needed some alteration. He actually meant to come to this strange land full of filthy sunlight and cheerful equines, he did! It's all part of his plan, that's right, and everyone else is just too stupid to realise its genius. None understand the brilliant master plan an intellect of his caliber produced. Yes, Greyseer Thanquol will let these pony-things teach him their secret magic and when he has learned all he can, improved by skaven ingenuity, he will use it to enslave their kind and return to Skavenblight at the head of an army!

He just needs to decide whether Luna or Celestia will make a better mount from which to gloat. Oh, and work out how their "Friendship Magic" but it will be Thanquol's!

A Warhammer Fantasy crossover, obviously. ON HIATUS unlike I get the feels for writing it back.

An experiment that I'll update in bite-sized chapters written when I need to let off some steam by writing a short and simple piece that amuses me. And nothing amuses me like Thanquol.

Will add tags as they become valid.

In the magical land of Equestria, two alicorn sisters raise the Sun and the Moon every day to give the world a night and day cycle, basic for the survival of life. There are also two alicorns who rule over two very core aspects of life and harmony itself. Those are Love and Friendship. While not as ancient as the two sisters, all princesses are essential to the world's balance.
This balance is also sustained by the hard-working ponies, who make the seasons change and manage the weather to fit their needs, so everypony has enough food and water, and every animal is also attended to assure that any of them are caught in the changes of seasons.

But what about the planet itself? What about Mother Nature?
This is the question that Gaia asks when she arrives to this foreign world. After so much work her son persuaded her to take a long vacation in Equestria, saying that she needed one and assuring her that he would be in charge now, and she must take a break. But what can a several billion-year old alicorn possibly do to pass her time in this land?

(SimEarth/MLP Crossover)
(Timelife of Gaia's life 'till the start of the story)

Instead of being killed in the cold Antarctic by Dr. Manhattan, Rorschach finds himself rematerialized in a strange new, pony filled world. He finds himself drawn into the lives of the ponies of Ponyville but some ponies fear that this sociopath will bring danger and darkness to an otherwise peaceful existence. Will the mane 6 help Walter Kovac find peace within himself or will he bring them all down with him in his cold views of reality and existence?

As Seen on Equestria Daily!
And our TvTropes page (By Crowrob0t): http://tvtropes.org/pmwiki/pmwiki.php/Fanfic/RorschachInEquestria

My Little Pony: Friendship is Magic and its likeness is owned by Hasbro Studios. Rorschach and Watchmen are owned by DC comics. All rights go to their normal original, intended owners.

(Gore tag is only for one short scene in ch2 due to description of blood in T story)
(It tickles me every time people erroneously think this is a self-insert)

Tobias has lived in Ponyville for almost two years now. He's been holding onto his secret, even though his friends keep worrying more about him every day. He focuses on the different jobs he does around town, trying to get by one week at a time.

He's become a welcome resident of the town, even if a few ponies still shout insults now and then because of his appearance.

Not a single one of them knows he's only been a diamond dog for two years and he's been trying to find a way home.

~~~~

What the crap am I doing in the feature box?!

That's like

And the top of the feature box the day after?!

I'm kind of glad I intended this to only be five or less chapters.

Second chapter given a great boost by feedback and proofreading with the help of:
FreedomFiend
Timetraveling Pony
m2pt5

Third chapter editing and feedback help from:
FreedomFiend
JimboTex

Twilight Sparkle has spent months researching chaos magic, developing a new spell to unlock magic nopony has ever experienced before. But when something goes wrong with casting, Twilight finds herself turned into a Draconequus and unable to control her new chaos magic. If she ever wants to be a pony again, there is only one who can help her learn to control her new magic.

Of course, learning from Discord was never going to be simple. And after a while, being a draconequus doesn't seem so bad anyway....

Based on the concept by Lopoddity

Editing by DB_Explorer
Proofreading by Mac349 (Ch. 1-11), Trippy998, Just A Fabulous Cat (Ch. 1-5), Doctor Candor and skysthelimit (Ch. 1-11).

Seath the Scaleless, White Dragon God of Verdite, Traitor to the Everlasting Dragons, Duke of Anor Londo, Grandfather of Sorcery, and now the new friend and mentor to Twilight Sparkle? What will happen when two like-minded souls from opposite ends of the morality spectrum match wits? And what will remain in their wake?

A somewhat more meta twist on a MLP/Dark Souls cross-over, inspired predominantly by a few pictures I found of Seath and Twilight together, and my bewildered discovery that for all of the stories on this site that cover these two franchises, there's only one that focuses on Seath the Scaleless and so far it hasn't seen any updates in over a year ( http://www.fimfiction.net/story/68621/scales for those curious).

For those who haven't played either the King's Field or Dark Souls games worry not. I'll do my best to either explain the lore of both in the story itself, or add an author's notes for anything that gets referenced.

UPDATE: New custom cover art at last! Courtesy of Cryophase ( http://cryophase.deviantart.com/ )

Editing is courtesy of lunarstallion

This story is a sequel to Lost into Shadow

The impossible has happened, through all the pain and darkness, Twilight Sparkle succeeded in her impossible mission...mostly. King Sombra is still plenty rough around the edges, but despite being an old dog he's making an effort to learn new tricks. Where will this new way of life take him? He has absolutely no idea, but with his queen to guide him, what could possibly go wrong?