A Thin Veneer

This is a Crossover written by committee. It can be found on Spacebattles and Fanfiction.net.

It describes a war between the Minbari Federation and the United Federation of Planets. In the beginning, a ship from the Earth of Babylon 5 and a Minbari ship chasing it go through a space anomaly. Captain Kirk's Enterprise finds them. The consequences extend into the next century, and the Vorlons get involved as well -- also as enemies of the Federation.

It can be found here.

Tropes:

 * Abusive Precursors: Vorlons march up one side of this trope and down the other. If it wasn't for helpful precursors on the Federation's side, this would be a much darker, and much more terrifying fanfic.
 * The Shadows also have a bit of this, as part of their backstory. However, as their style is more "Infiltrate and learn," rather than "appear as gods," they more quickly learn about the Federation and its benefits, and leave not that long after they're introduced.
 * Alternate Universe: An alternate universe Admiral Janeway from the future, Voyager, and a Minbari warship travel to the ATV universe to deliver a warning about the Vorlons and provide weapons and technology from over one hundred years in the future. This scares Kirk, as Starfleet has strict rules against this sort of thing, and if Janeway is willing to break them, things must be very serious.
 * Arson, Murder, and Jaywalking: Inverted with the Gorn. While the first four ships listed are almost certainly an attempt to tease the Federation, being named Smaug, Fafnir, Mothra, and Rodan, the last is registered as
 * Crossover
 * Curb Stomp Battle: Well, just about every single time the allies go against the Minbari, and even sometimes the Vorlons. The B5 powers are just that outmatched in terms of speed, firepower, durability (at least while the shields are up), and actual combat experience. It's hard not to feel sorry for the Minbari.
 * Even First Ones Have Standards: None of the other "elder races," or "first ones," such as the Metrons, Medusans, Organians, or even Q like the Vorlons. The Shadows don't like them either, but they have a history to back it up.
 * Everything's Better With Dinosaurs: The Federation classifies Gorn ships by Dinosaur name. The flagship of the Gorn group that arrives at Beccara Alpha One is a Tyrannosaurus Rex class dreadnought.
 * External Retcon -- the Vorlons led the Dominion into the Dominion War. The Vorlons and the Dominion are for Order, and the Federation and its allies are sheer chaos just a wormhole away.
 * Also, the Vree's "Dimensional Slip" technology came from reverse-engineered tech from an abandoned Iaconian outpost.
 * Foregone Conclusion: The events of this story are interspersed with occasional looks into the future of the ATV-verse, including Sisko and Picard. The war ends with the remnants of the Minbari Republic signing an agreement with the Federation/Klingon alliance, followed by close to a century of cold war with the Vorlons, who eventually lead the Dominion to war with the Federation and help along the Ciona Imperex in their attempt to dominate the Alpha Quadrant races in the name of order. Meanwhile, the Narn Regime and the Centauri Republics join the United Federation of Planets.
 * Fusion Fic
 * How Unscientific -- when the ship from Babylon 5's Earth realizes for the first time that the new ship has warp drive -- which is strictly forbidden by Babylon 5 physics, but which is the only way to explain the sensor readings.
 * Humanity Is Infectious: The fic continues the Babylon 5 tradition of making humans community builders, and the prologue reveals that the Narn and the Centauri have joined the Federation in the future.
 * Someone at Starfleet decided to classify Gorn ships with dinosaur names. When the Gorn find out, the Gorn ambassador thinks that this is an honor, and their battleship program is rumored to be called Godzilla! Four of their ships that come to the Earth Alliance's side of the galaxy are named after dragons or monsters: Mothra, Rodan, Fafner, and Smaug.
 * I Do Not Own -- and neither does anyone else. Explicit permission is given for anyone to copy this story as long as they leave the credits. The credits mention many works, including all vs. of canonical Star Trek extant at the time.
 * It Got Worse: The prologue reveals that
 * Moral Myopia: The Minbari attitude toward their defeats.
 * Later, the Minbari are shown up at this by the Aschen.
 * Mythology Gag: Sheridan, when he first appears, is surprised that he doesn't feel disgust at the idea of half-human hybrids in the Federation, or at humans mating with aliens. In the canon Babylon 5 story, he eventually married and had children with Delenn, a Minbari.
 * Normal Fish in A Tiny Pond: Many Federation technologies are considered normal, even weak for the setting, but are very effective against the Minbari simply because they have had no exposure to these technologies.
 * Of particular note are tricobolt explosives. While they've been largely phased out in the Federation due to the prevalence of more effective antimatter explosives, the tricobolt devices have the unique benefit of royally screwing up Minbari gravity drives.
 * Shout-Out: The Gorn battleship program is rumored to be called Godzilla. The names of two of the ships in the mini-fleet they bring include Mothra and Rodan, more Godzilla monsters.
 * Another ship is the Smaug, named after the dragon from The Hobbit.
 * When Kirk is going over some of the officers participating in the war, he mentions that he used to work on a ship with Ted Stryker and Buck Murdock, and even mentions Stryker's Drinking Problem.
 * Tyrannosaurus Rex: The Federation has labeled a Gorn dreadnought design as the Tyrannosaurus Rex-class ship.