Diablo Crossover.

The Archangel of Justice destroyed the Worldstone to spare Humanity the corruption Baal infected it with. The force of its death knell shatters Mount Arreat and sends Tyrael hurtling across the endless planes of reality. He falls upon a world untouched by Angel or Demon, far from the sight of the High Heavens. So far, in fact, that he fears he will not be reborn from the Crystal Arch.

Wounded and near death, hope appears in the form of two strange creatures bearing the power of night and day.

Tyrael now faces a time of recovery as his power slowly heals within a body fashioned for him by his saviours. Justice Incarnate tastes for the first time the life of a mortal, and it is a strange, confusing experience .He has been left in the care of one Twilight Sparkle to learn of this world.

After all, where better to find peace and harmony than Ponyville?

Act I - The Root of Evil
Act II - ????????
Act III - ???????
Act IV - ???????

[Cover image used with full permission of the owner. Go on, go have a look at Chagial's stuff.]

This story is a sequel to The God Empress of Ponykind

One thousand years ago, Luna, Warmistress of Equestria and sister of Empress Celestia, fell to the powers of Chaos and plunged Equestria into a brutal civil war. The Traitors were defeated, but not before Luna made the ultimate sacrifice and was sealed away in the Immaterium with only the soul of a slain Primarch to keep her company. For a millennium she has been locked away, waiting for a chance to return to her home and her sister.

Now, she has been freed from the Immaterium, and as she takes her first steps in a new Equestria, one ruled by the powers of Harmony, only one question remains:

Does Equestria still need the services of a Warmistress?

Comments may contain spoilers. YOU HAVE BEEN WARNED!

Also Tropes. Please contribute.

Twilight Sparkle had been looking forward to a quiet, relaxing day with a friend, and at first it seemed that Fluttershy could provide just that. But when Twilight makes a rather unsettling discovery about the pegasus – and her unusually sanguine appetite – the knowledge proves to be anything but relaxing...

Dear Princess Celestia,

I'm sorry I haven't written in a while. Things seem to be falling through the cracks lately. Spike thinks I should go see the doctor, but...

This story is a sequel to Justice

Worker's dreams have taken a turn for the worse. Feeling trapped, unable to talk about his experiences and unable to stop the near-nightly terrors, he wonders if he should reach out to the Princesses. It never occurs to him that these nightmares might be something more.
This is the final story of a trilogy. The first part is Order from Chaos, and the second is called Justice.

And you're not gonna believe what happens next!

A Metroid Crossover

A meteor, resistant to magical manipulation, crashes in Equestria, Planet Equis, and soon spreads an unknown poison throughout the land. Containment is all but failing and the Princesses have little power to stop the spread of the Great Poison. The Elements of Harmony are of little use as no knowledge exists of this threat that consumes all life. Help comes from a certain Hunter, clad in metal.

Samus Aran will not only fight for her life as always, but her own sanity as well as these ponies that she begrudgingly starts seeing as allies. New horrors and abilities await her as a reason to fight slowly festers within her, possibly unlocking something she had been denied for so long: Friendship.

Notes and Resources:

This takes place after Echoes. The events of Corruption will have not happened yet. In terms of MLP, consider everything up to and including the Crystal Empire. Princess Twilight does not exist here, etc. The official Metroid Timeline can be found here.

As well, this story references the manga in many places. Reading of it is not required and I try my best to explain the context, but if you're interested, both volumes can be found here.

EDIT: This story was written over two and a half years, beginning in 2013. You'll probably notice the difference in writing as the chapters progress.

This story is a sequel to Metroid Equis

With the culmination of events on the BSL Research Station, Samus Aran is finally able to come back to Equestria, Planet Equis; to come back home. Much has changed in her absence, but it is still the friendly, peaceful, welcoming planet and nation that she left behind two and a half years prior. With the Space Pirate threat neutralized and the secret, illegal Metroid militarization programs destroyed, it appears that Samus can finally take another massive breather with her friends and enjoy some well-deserved rest, recovery, and relaxation. The galaxy is finally at peace.

At least... for a short while.

A new enemy, one much closer to home, soon rears its head, threatening all of Equestria and Equis with complete and utter annihilation. Their mission: revenge. Samus will fight with all of her being alongside her allies against an enemy who would like nothing more than to see all that she holds dear, including her home planet, completely razed. In so doing, her cunning, ever determined enemies unleash a weapon so unexpected, so eerily familiar yet horrifically foreign that even Samus herself just might prefer the late Ridley or the SA-X...

Editing Team: Random_Dragon; ToxiClay

The Metroid Timeline/Chronology (confirmed by Nintendo) can be found here.

Canon Considerations
MLP-FiM: Up to AND including "Magical Mystery Cure." (Seasons 1, 2, and 3)
Metroid Series: Everything up to AND including Metroid Fusion (Including original mangas. See official timeline above). So, effectively everything.

On one of her regular hunts for gemstones, Rarity discovers a treasure trove beyond her wildest dreams... and the lavender-scaled dragon who collected it. Despite a rocky first meeting, Rarity and Greenfire soon find themselves drawn to each other more and more. But the question remains: How did a young dragon end up in the Everfree Forest all alone?

An alternate universe story that puts our favorite purple dragon and his beloved fashionista into a slightly different situation. Art used with permission from the wonderful ArtisteFish!

Now with a TV Tropes page! Thanks go out to Poptard and whoever else might feel like editing it.

Fan Works
Climbing the Cliff by Pia-chan (from chapter 5)
Such a Pleasant Chat by Fukaï
Some Form of Tea by Pia-chan (from chapter 4)
Promo Animation by CMagic (mild chapter 6 spoilers)

Reunited with his beloved Shield Knight, Shovel Knight continues journeying with her, just like old times.
But when what appears to just be run-of-the-mill loot ends up teleporting the pair to a new dimension,
The pair will find themselves not only facing a new journey. but new challenges within themselves as well.

*Warning- minor spoilers for Shovel Knight*
__________________________________________________________________

7/21/2014- We made the popular stories list! Thank you everyone! Who knows, maybe we'll make the feature box? Perhaps?
7/22/2014- I don't even... we actually made the feature box.
4/3/2016- We once again made the feature box. Thank you all again for your continued support of the story.