Friends of a Solar Empire

A crossover between My Little Pony Friendship Is Magic and Sins of a Solar Empire, written by Dalek Ix.

Equestria has been part of the Trade Order for a thousand years, enjoying prosperity. But as the Summer Sun Celebration looms and Nightmare Moon's return is on the horizon, forces align on both sides.

It can be found here and here. And here's an index on the Spacebattles forum.

Needs More Love and A better description.

Friends of a Solar Empire contains examples of:

 * Ace Pilot: Pegasi and Griffons in general. That someone managed to find a way to let them control fighter craft with their wings helps.
 * All There in the Manual: The Spacebattles threads.
 * To elaborate: Most of the fic's World Building is on the forums, in the form of "extra documents" written In-Universe (for instance, Cloudsdale is described in a tourist brochure). There's also some elaboration of story elements in the discussion. None of this is necessary to understand the fic, but definitely helps flesh out the story.
 * And I Must Scream: Word of God on what happened to Discord. The Traders sealed his statue in a small ship, put it on auto pilot towards empty space, and kicked on the FTL. A ship can only drop out of FTL if it enters a strong gravity well, and their are very few planets or stars in the ship's path. And Discord is still stuck as a statue during all of this.
 * To make matters even worse for the bastard, the overall flight path is perpendicular to the plane of the galaxy, so he's heading straight into intergalactic space, the emptiest place in existence. There won't be any conflict to free him for a long time.
 * Also what happened to some members of the Horizon Corporation, also by Word of God. While the Universal Trade Sanction (which makes them unable to even buy food) was handed down by the Investigation Directorate, the various factions of the TEC also handed down their own punishments...including Cognizant Cryocontainment.
 * Author Appeal: Crossovers. This is the same guy who brought us A Hero.
 * Cruel Mercy: By Word of God what happened to the people running the lab that Twilight came from.
 * It's less Cruel Mercy and more an indirectly-caused Fate Worse Than Death. Not they they didn't deserve it, in any case.
 * Cassandra Truth: Pinkie Pie keeps telling high command that their orbital fighter bays could really do with some flak-cannons. Predictably they take no notice.
 * Averted when Celestia tells the TEC that her currently insane sister will be returning to wreak vengeance soon. They send a battlefleet. And Admiral Kol.
 * Disproportionate Retribution: The Trade Order's Investigation Directorate. Their response to the actions of the Horizon Corporation was to hire a Marza-class dreadnought to blow up the asteroid their facility had been built on, and then ban the rest of the Traders from doing business with them. Not even to buy food.
 * ...Disproportionate?
 * Fictional Document: The "Extra Document" files.
 * Fusion Fic.
 * Gattaca Babies: Twilight Sparkle.
 * Gosh Dang It to Heck: A human colonel is described as wearing "an apple-eating grin" when a crazy shore leave involving Fluttershy is mentioned. An odd example, as it appears in narration, not dialogue.
 * Proud Warrior Race: Gryphons, Pegasi and the Kol family. It made them oddballs in the peaceful Trade Order. Then the Vasari turned up.
 * Humans Are Warriors: As explained in a letter to the Gryphus Republic the humans of the Trade Order are peaceful by conscious choice, not by natural inclination.
 * Hypercompetent Sidekick: Lampshaded; Rarity thinks the only reason she survived in position to become competent was thanks to the local Colonel Badass.
 * Mega Corp: The TEC is an alliance of these; Rarity's ship is even owned by one.
 * Noodle Incident: Apparently, Fluttershy joined Rarity's crew in some rather over-the-top antics on their last shore leave.
 * And Colonel Rekav is no longer allowed to gamble anything, for some reason.
 * Sci-Fi Writers Have No Sense of Scale: Averted. Hard. The author goes out of his way to make it clear that space is fucking huge. He even describes Twilight and Spike seeing the TDN Novus as a tiny point in the distance as a minor miracle.
 * Shout-Out: Rainbow Dash's callsign is "Starbuck".
 * Equestria's Argonev starbase is called the Kasztanka.
 * The Stinger: Both chapters so far end with flashbacks to Twilight's past, in the form of "holo-vids".
 * The High Queen: Princess Celestia, who is still ruling Equestria, controls most of the pony species by the strength of tradition and by being an honestly good ruler and noted as being one of the most important members of the TEC.
 * Tranquil Fury: In a flashback, A TEC fleet arrives at a planet conquered by the Vasari, and finds it turned into a giant slave camp and strip mine. When soldiers are sent down on a rescue mission, Rarity calmly orders them to shoot any Vasari they see, no survivors. Even the resident Colonel Badass is surprised.
 * Transhuman Treachery: A predecessor to the Trade Order tried to do this, in a very complete way. They're the reason why Transhumanism isn't allowed. (See the Complete Monster entry for details.)
 * Officer and a Gentlepony: Rarity.
 * Unusual User Interface: Pegasi and griffons control their fighters with their wings.
 * Even Rainbow Dash finds it a bit odd, musing that it came about because "a human (took) a foal’s suggestion too seriously".
 * World Building: Arguably one of the most popular aspects of the fic.