Standard Sci-Fi Setting

"In the far future, the [human group] fights a pitched battle against the mighty [alien name] Empire, but deep in the mysterious [region of space], among the ruins of the past, a darker threat looms."

Does the above sentence sound familiar? It should. It's probably the single most popular Space Opera premise around. In fact, you could even call it the Standard Sci Fi Setting. Typical features of the Standard setting include:

Technology:
 * Easy faster than light travel. This comes in several flavors:
 * a Portal Network of "jump gates," "wormholes," or so forth, or
 * a web of Hyperspace Lanes spanning the galaxy, or
 * "warp drive," "jump drive," or some other kind of Faster-Than-Light Travel through Subspace or Hyperspace.
 * Space Is an Ocean and the Standard Sci-Fi Fleet sailing it.
 * Mystical/Metaphysical elements, generally including Psychic Powers, Life Energy, or something else similar to Functional Magic (usually associated with either Highly Evolved Human Aliens or Sufficiently Advanced Aliens).
 * Very little, if any, of The Singularity, except possibly as a justification for Sufficiently Advanced Aliens. Humans themselves will almost never be post-Singularity. Transhuman Aliens and Ridiculously Human Robots will be subject to Fantastic Racism, possibly because there is No Transhumanism Allowed.

Population:
 * Humans by Any Other Name, usually "Terrans".
 * Neglectful Precursors.
 * An ancient and hidebound proud warrior race who may double as Scary Dogmatic Aliens. Their ships will typically be purple, green, or gold. If anyone has an Enemy Civil War ready to break out, it will be these guys. May experience an Enemy Mine situation with the Humans by Any Other Name if a common threat appears.
 * A genocidal alien race that's either The Virus, Planet Looters from "beyond known space" or a full-on Horde of Alien Locusts. Rogue robots out to kill all organic life are another common variant. These guys are usually what wiped out the Neglectful Precursors. Their ships will usually be sleek and angular when they aren't organic blobs. Either way, their ships tend to be red, purple, black, or other "evil" colors. May provoke the other races into uniting against them.
 * A wise/spiritual race decked out in Crystal Spires and Togas. These are often Human Aliens and/or Space Elves, possibly the Neglectful Precursors, if they're already extinct. Their ships will be sleek, but more rounded, and usually colored white, silver, or blue (gold or copper/bronze is rare, but acceptable). If there's a metaphysical aspect, these guys will be brimming with it more than any others. Bonus points if they have a rival sect called the "Dark" something.
 * Space Babes, usually blue or green-skinned.
 * The Greys or Little Green Men, the two most common type of aliens used due to them being from alleged-alien sightings. Their somewhat less common cousins, The Reptilians, pop up from time to time. The former tend to be the Proud Scholar Race, while the latter tend to be the Proud Warrior Race.
 * As many as a dozen other races of little to no consequence beyond certain characters or as background elements. May include Robots, aforementioned rebel/heretical sects, Alien Slavers, an Eldritch Abomination, non-locust Zombies, Robot Zombies, Robot Eldritch Abomination that command zombies, and on down the line.

Factions:
 * The Federation, The Empire, or other space faring humans that fly big gray battleships and little gray fighters, and comprise the bulk of the Standard Sci-Fi Army. They have a good chance of being descended directly from the Neglectful Precursors.
 * A "rebel" faction fighting against one of these groups is a frequent option.
 * Space Marines if the film was made after Aliens or the book written after Starship Troopers; guys with ray guns and tight outfits if before or homaging before.
 * Oh, and Space Pirates. Space pirates are inevitable in such a setting.
 * In some more recent works, one or more of the above factions might have "Incorporated" in their name somewhere, but they'll still be the same for story purposes.

Plot:
 * The Standard Sci Fi History as Backstory.
 * An epic Space Battle where the future hangs in the balance as a result of it, or leading up to it.

A typical plot involves the humans fighting the Proud Warrior Race Guys until one or the other stumbles upon the ruins of the Neglectful Precursor civilization and unleashes the evil third race. Then a bunch of people die, there are lots of a cool explosions, and the first two races team up to take out the genocidal aliens. Usually they have to track down some Forgotten Superweapon and use it to destroy the alien queen/mothership/homeworld, thereby saving the galaxy... for now.

Not surprisingly, this setting tends to fall toward the "soft" end of the Mohs Scale of Sci Fi Hardness. Examples come mostly from TV, Movies, and especially video games, where scientific accuracy often takes a back seat to awesome visuals and an engaging storyline. Compare Sci Fi Kitchen Sink, which takes a Standard Sci Fi Setting, then crams as many other Speculative Fiction Tropes into it as it can.

Comic Books

 * The Legion of Super Heroes has a 1000-years-from-now setting that was so close to the Standard Sci Fi Setting (at least until the threeboot) that you'd think it's clearly based on Star Trek had it not actually preceded Trek by a good 8 years. FTL? Original has warp drive, reboot adds Stargates. Threeboot isn't so stock, as transmatter gates have rendered spacecraft obsolete. The United Planets is The Federation (it was at least once erroneously called "the Federation of Planets"). Mysticism? Check. Not just psionics, but explicit magic, since it takes place in the Fantasy Kitchen Sink DC Universe. Proud warrior race? The Khunds, sometimes specifically based on Klingons. Alien hordes? Check. Space pirates? Check.
 * DC Comics' Star Raiders graphic novel features one of this. Easy Faster-Than-Light Travel, Psychic Powers, Scary Dogmatic Aliens, The Empire, La Résistance, and lots of Epic Space Battles.

Film

 * Star Wars is more or less the Trope Codifier in modern fiction. While it's far from the first and has its own unique quirks, Star Wars made the Standard Sci Fi Setting palatable for the masses.
 * Equally important is Aliens. While the movie lacks other alien civilizations and faster than light speed, it single handedly defined human culture, technology, military, and visual style for Standard Sci Fi Settings for decades to come. Babylon 5, Starcraft, Free Space Halo, and Mass Effect are more or less directly based on this movie.

Literature

 * Star Trek may have picked this trope up from the older pulp science fiction like the Lensman series.
 * The Saga of Seven Suns uses this, but it sometimes borders on Cliché Storm. However, as with everything, Your Mileage May Vary.
 * The Uplift Universe of David Brin.
 * Andrey Livadny's The History of the Galaxy series fits many parts of the trope. There's the Confederacy of Suns, the late Earth Alliance, animal-like Forerunners, easy FTL travel, Space Marines (although less of the Starship Troopers variety and more of the piloting Humongous Mecha kind), Space Pirates, and several Neglectful Precursors (many of whom are still around). There's a notable absence of Proud Warrior Race Guys and Crystal Spires and Togas. Rogue robots are the main theme of several novels (one novel deals with a completely automated gigantic alien mothership attacking a small human colony). There is only one race of Human Aliens, and they're blue.
 * Pandoras Star does it brilliantly.
 * Tour of the Merrimack fits this, with the US as The Federation, Palatine as the Proud Warrior Race at war with them, and the Hive as the Horde of Alien Locusts that forces the two into an Enemy Mine.
 * The Humanx Commonwealth universe, with the titular Commonwealth as The Federation, the AAnn as The Empire with elements of Proud Warrior Race, scads of Precursors, including the Xunca as the Neglectful Precursors, along with their Lost Technology, and the galaxy-devouring Great Evil as the Bigger Bad.

Live Action TV

 * Star Trek is one of the main sources of this setting and has used the basic plot for both The Next Generation with The Borg as The Virus and Deep Space Nine where they fought against the Dominion, not to mention countless one-off episodes that have used this plot to preach An Aesop of cooperation.
 * Andromeda had The Commonwealth, the Nietzscheans, the Magog, and various Precursors. It was following the standard plot pretty well until the mysticism took over and it got weird.
 * Stargate SG-1 - originally a planet-of-the-week adventure centered around the titular device, with not that much overall continuity - mutated into this slowly, picking elements over time (especially starting with season 6), although it took the addition of Stargate Atlantis to complete the transition. The Ancients are the Neglectful Precursors, the Wraith and Replicators are the genocidal planet looters or Planet Eater (and the former wiped out the Ancients), the Tau'ri (us, modern Earthlings) are the spacefaring humans with grey ships, and the Jaffa are Proud Warrior Race Guys serving the Goa'uld, a race of Scary Dogmatic Aliens.
 * The Stargate Verse differs from the Standard Sci Fi Setting in a number of ways. First and most importantly, the characters are mostly modern Americans, and all the high-tech stuff is unknown to the general world simply because of a Masquerade. Morality is more black and gray than in many Sci-Fi settings because the military often has to Shoot the Dog. This is almost unique in that most of the protagonists are Genre Savvy. However, by the end of the series Earth basically is playing the role of The Federation, thanks partially to the Very Neglectful Precursors and partially to Earth's role in freeing the Proud Warrior Race Guys from millenia of slavery.
 * Babylon 5 has the Narn as the Proud Warrior Race Guys, The Minbari as the Closer to Earth race, and the Shadows and Vorlons being both the Neglectful Precursors and the Planet Looters at the same time, in varying amounts.
 * It's worth noting that B5 sets the cliches during the first season and then proceeds to Deconstruct them in short order. The Narns mellow down considerably, the Minbari demonstrate serious flaws and hypocricy, the Centauri who initially seemed to be ineffectual, comical figures develop a darker edge, and so on. The less significant races keep to their cliches pretty tightly, though - the Drazi for example demonstrate the Proud Warrior Race traits quite a bit, when the Narn set them aside.
 * The dark side of the Minbari is shown almost right away though they always have an attractive side as well as a dark side and the Narns don't really mellow although G'kar does(they simply change from the would-be Empire into The Revolution Will Not Be Civilized). The Minbari curiously are both a Proud Warrior Race and a Proud Scholar Race. The Centauri are a big surprise; no one would expect them to be good enough at fighting to be brutal conquerors anymore. Earth Gov is a surprise; we expect it to be The Federation and instead it evolves into a Police State but with the twist that it is an isolationist and nativist Police State rather than The Empire and spends more time supressing internal rebellion then in aggression. Interestingly most of the characters including the command staff and all the main ambassadors, at one time or another end up as La Résistance to their own government in various ways and degrees. The Vorlons are a real surprise turning out to be almost as evil as the shadows except for kosh. The shadows follow the generic description above almost exactly being the Sealed Evil in a Can that forces leaders from other races to form The Alliance.
 * Firefly is arguably a Standard Sci Fi Setting adapted to fit closer to the realistic end of the Sliding Scale of Realistic Versus Fantastic. It clearly has many of the elements, as listed below, but lacks the more fantastic ones like aliens.
 * There's no faster-than-light travel, but it's still easy to travel between dozens of inhabited planets and moons.
 * Space Is an Ocean
 * Psychic Powers: River.
 * The Alliance and the Independents.
 * The Virus: Reavers, who come from the edge of known space and turn some of their victims into Reavers.
 * Space Pirates: commonplace.
 * Epic Space Battle where the future hangs in the balance: the series was seemingly slowly building up to this before it was cancelled. The movie does give us one.
 * Mega Corp: Blue Sun.
 * Plot:

Tabletop Games

 * Warhammer 40000 is something like this painted black and covered in skulls, with a lot more races, a great deal of Gothic Punk and a heaping helping of Cosmic Horror Story.
 * Rifts's Phase World setting. The Consortium of Civilized Worlds is The Federation, the Transgalactic Empire is The Empire of Scary Dogmatic Aliens, and the Crystal Spires and Togas are handled by the United Worlds of Warlock. Any examples of The Virus or Planet Looters are, for the time being at least, nascent and/or lying in wait.
 * Fading Suns uses a setting which falls nearly exactly into this trope. The Excints Ur have littered space with floating portals that allow for travel ans strange technologies, the Known Worlds are United under the new Phoenix Emperor, harboring numerous races amongst the humans. The Vau are the wise race living in their own world outside the empire. And constantly straining to get in the Empire are the Symbiots, a metamorphic plague/virus/infestation. Of course, space pirates, political conflicts and psychics manifestation abound.
 * Traveller has many fairly familiar tropes. However it develops them extremely well.
 * Precursors=Ancients
 * Humans "classic"=Solomani
 * Venerable Race=Vilani
 * Psionic Race=Zhodani
 * Proud Warrior Race=Aslan
 * Space Pirates=Vargr
 * The Federation=The Imperium

Video Games

 * The Halo games have less of a mystical bent than other examples but otherwise fits perfectly. The Covenant are the Scary Dogmatic Aliens, The Flood are The Virus, and The Forerunners are the Neglectful Precursors. The plot is largely as above.
 * Free Space: The Terrans play this trope completely straight, but while the Vasudans certainly fit the ProudWarriorRaceGuyss stereotype, the xenocidal Shivans are slightly anomolous. Whilst certainly Color Coded for Your Convenience, from beyond known space, and responsible for wiping out the (downright maliciously imperialistic) Ancients, the Shivans are neither The Virus, a Horde of Alien Locusts, nor Planet Looters. They don't bother with conquest, looting, or assimilation, all they care about is getting to the xenocide. FTL drives are both subspace drives and require a Portal Network of jump nodes to travel between systems. There is a total lack of any metaphysical aspect or aliens aside from the core 3 races. Aside from those minor details, it's a Standard Sci Fi Setting.
 * Starcraft: The Terrans are the humans, the Protoss are the Warriors, the Zerg are the Horde of Alien Locusts and the Xel'Naga are the Precursors. Psychic Powers are everywhere.
 * Galactic Civilizations used this as part of its "nothing you haven't seen before" approach to game design.
 * Mass Effect, though the Spectres are closer to Space Secret Agents than Space Marines. Otherwise, replace The Virus with a robotic Eldritch Abomination and throw the Krogan in as the Proud Warrior Race Guys.
 * It's the perspective of many that humanity is the come-lately Proud Warrior Race Guys. They're trusted enough to be considered for the Council and Spectre membership, but not that much more than the Krogans.
 * Don't forget the Turians, they have as much claim to it as the Humans if not more.
 * Also, don't forget, very literal "Robot Eldritch Abominations that command zombies" (if you see Husks as zombies).
 * The Asari double as both psychic Space Elves and an entire species of blue-skinned space babes.
 * Freelancer is kinda like a conspiracy story with Casual Interstellar Travel, Space Clothes to some degree (mostly the LSF uniforms), . There are no Psychic Powers though, and the closest thing to The Federation are the four Houses that are kinda like our countries.
 * Halo's forerunner, Marathon, decides to mix things up. You have the so non-proud warrior race/Alien Slaver Pfhor, then the indigenous Flick'ta replaced the planned fungal zombies, and an Eldritch Abomination shows up in the final game. The S'pht and their long-lost cousins Enemy Mine with the humans to take on the aforementioned threats. Other than the above alterations, the plot pretty much follows the above discription to a T.
 * Sins of a Solar Empire. The Trader Emergency Coalition (or TEC) is The Federation, The Advent are Closer to Earth, Vasari are Planet Looters, and there's Space Pirates and easy faster-than-light travel, by means of "phase jumps" along "phase lines" in "phase space." Most beyond that is uncertain, since the developers decided to drop a campaign in favor of better multiplayer. Reviewers did not take kindly to this.
 * The Star Control universe does all of the above both straight and with a light-hearted tone.
 * Sword of the Stars has a wealth of this, although it plays with a lot of them, like different races using different faster than light drives (all the standard methods are used, but by different races) and a wealth of background information on the different races and their inner workings that would put several sci-fi TV series to shame.
 * Lovingly parodied by Gratuitous Space Battles; the back story is pure fluff, used as a tongue-in-cheek excuse for the eponymous space battles. The main thing it lacks is the wise Crystal Spires and Togas civilization: the Tribe comes close, but they're Well Intentioned Extremists, just as violent as everyone else.
 * The Wing Commander series is all about this. Initially it's the Terran Confederation versus the Kilrathi Empire, but in the fifth game the Horde of Alien Locusts shows up.
 * EV Nova is no exception to this trope. The main twist is that all the major factions are human (no GSSBs, Greys, or lizardfolk). There's also no Horde faction, and since the game takes place entirely in space, Space Marines are present but largely ignored. As for the precursors, little remains of their leavings and even less is understood; they're just gone.

Web Comics

 * Zap has a fairly similar setting. Aliens (almost all humanoid), psychics, A Is with very human-like personalities, an Empire (in all but name), a Government Conspiracy or two, Space Pirates, lost technology, Mad Scientists and Bungling Inventors, a hot redhead, etc, etc.
 * Buck Godot: Zap Gun for Hire takes place in a setting very similar to this, except Humans are relative newcomers to the Gallimaufrey and only become notable due to . Oh, and their invention of the popsicle.

Web Original

 * Averted / subverted in Orions Arm, which tries to be a hard sci-fi setting without sacrificing any of the appeal of the more traditional Space Opera. The result is a transhumanist setting ruled by godlike Artificial Intelligences called Archai, which have experienced not one, but several Singularities and rule over their lesser subjects like benign deities. Advanced nanotechnology and relativistic spaceflight are commonplace, and while true FTL is impossible, wormholes and Reactionless Drive technology have been created by the Archai. Creating Life is also not that hard, and baseline unmodified humans represent only a tiny part of the extremely diverse terragen (originating-from-Earth) civilization composed of genetically modified transhumans and sentient animals and sentient human-animal hybrids, cyborgs of all kinds, sentient robots, and several kinds of infomorphic lifeforms. And that's just the lower toposophic (read: number of Singularities crossed) levels, before you get to the various planet-sized AIs, Dyson Sphere-sized AIs, and the wormhole-based AIs that are the higher toposophic beings (the 'godlings' and full godlike Archai). And that's just the terragens, not counting the handful of very alien aliens that the setting features. Basically, any technology or lifeform that isn't banned outright by physics in in there, somewhere.