In the StandardSciFiSetting, trade is common between star systems. Sometimes a planet becomes so specialized that it focuses on a certain commodity or service. Maybe it's building weapons or providing doctors. Whatever it is, the world trades this resource with other planets, becoming renowned for the export.

This trope isn't about a single {{Planetville}}; It focuses on the big picture on how individual worlds interact with each other. Subtrope of PlanetOfHats, though any location (an asteroid, small moon, space colony) can serve as this. Compare/Contrast SingleBiomePlanet.

Most SF tales assume CasualInterstellarTravel; it's possible for Slower Than Light ships to transport commodities, but the items being traded would have to be of extreme value to justify the high cost and long wait. It also often crops up if the setting is confined to a single solar system, which is slightly easier to justify as it only requires somewhat CasualInterplanetaryTravel.

Well done versions of the trope will explain that a planet is widely known for its major export, while its other industries are neither profitable nor popular. It could also be used for comedic effect, by exaggerating it to the point of absurdity.

Economics aside, a planet has other values: political, cultural, religious, and military. The importance of the export directly influences the importance of the planet. For example, the Planet of Phlebotinum would have a lot of power and an armada protecting it. However, the Planet of Toasters would lack any economic influence and maybe warrants a corvette for protection. Meanwhile, the Planet of Judges, Robes, and Powdered Wigs would have political clout, but lack economic influence. The amount of protection depends on how much influence they have with their neighbors.

May correlate with MultipurposeMonoculturedCrop, if the One Product is farmed instead of manufactured.

!Planet Types

[[folder: Main Locations]]

Political center of an interstellar government and a place of intrigue. The [[ShiningCity apex of culture and power]], but also of [[DeadlyDecadentCourt decadence and corruption]]. Highly valued, expect the world to be well protected...unless no ships are available for whatever reason. Capitals of various space Empires tend to be [[CityPlanet highly urbanized]]. Also the center of the vast [[{{Adminisphere}} bureaucracies]] governing the stars.


Offers [[MinovskyPhysics scientific curiosities]] and unusual matter (monopoles, antimatter, mini black holes), or a site of strange astronomical happenings (such as wormholes or black holes). If extra-terrestrial life is rare, then worlds with alien biospheres would be of interest. Scientists and corporations would love samples of strange matter, or get a chance to observe such [[NegativeSpaceWedgie strange phenomenon]].


Center of mass production. Presented as [[NightmarishFactory industrial nightmares]], with [[PollutedWasteland polluted skies]] and [[MegaCity large]] [[IndustrialGhetto crowded cities]]. Its products can include technology, but it's often less than state-of-the-art. Focused more on [[TheEngineer production/engineering]] rather than research. Often ruled by tyrants or a [[OneNationUnderCopyright corporatocracy]].


Grows crops and raises animals. There are typically two types:
#Worlds that only produce foodstuffs to feed places that can't produce enough subsistence, such as urbanized worlds or space stations. Not much value, except if the [[CripplingOverspecialization importer is totally dependent on them]]. Then the planet becomes an AchillesHeel. Often rural in nature, but hydroponic bays and protein vats are not unheard of. Can be large tracts of cultivated land, or water farms on oceanic worlds.
#Planets which harvest an [[AppliedPhlebotinum important crop that has unique attributes]]. Such flora or fauna could be used for medicinal uses, especially if it's a drug. Then it would be more profitable than a world that exports beef. Such farms tend to be jungle or death worlds.

Such worlds are usually peaceful, but could become unstable if the political situation changes. The local folk are [[CultColony religiously devout]], originally settling such worlds to seek ascetic lives. The home of many a [[FarmBoy young]] adventurer and military [=/=] mercenary recruit - life on a farm world lacks excitement, and encourages wanderlust. Commonly [[MetalPoorPlanet metal poor]], justifying why they don't have much industry.

!!![[ForbiddenZone Forbidden]]

Location of dangerous nature that no one visits. Could be a colony destroyed by plague or [[HordeOfAlienLocusts infested by alien locusts]]. Whatever the reason, the planet is [[GhostPlanet no longer of any value]], covered in ruins or wasteland. Only [[ForbiddenFruit adventurers would willingly travel to these worlds]].


Point or area where a [[OurWormholesAreDifferent wormhole]][=/=][[CoolGate stargate]][=/=][[NoWarpingZone minimum hyperlimit]] exist that facilitates [[FasterThanLightTravel FTL transport]]. Vital for rapid transport (unless you want to slog decades across space), and in the cases of a PortalNetwork, a chokepoint.


Exports [[PrivateMilitaryContractors Mercenaries]], coming in two varieties:
# SuperSoldiers, often living in a military culture and/or harsh environment to develop their skills.
# CannonFodder, hired out only because the planet has nothing else to sell.

Along with these, various settings have specialized forces: armour warfare, Special Ops, sapping, urban warfare, etc. Life on these worlds tend to be tough, and often produces [[ProudWarriorRaceGuy prideful fighters]]. Could be ruled under the military or an authoritarian society. Oddly enough in fiction, there are plenty of [[LibertariansInSpace Libertarian cultures]] that don't mind setting up such worlds.


Harvests natural resources, often rare metals, minerals, or gases needed for industry.

Influence of a Mining world is dependent on what it gathers. A world mining Tin isn't going to be much value. However, a planet collecting Helium-3 (which can be used for fusion reactors) are going to be richer and better protected. Such places can range from terrestrial planets to asteroids to gas giants.

As business concerns, they're [[CompanyTown run by whoever owns the mines]]. Governance varies, but life tends to be hard and people poor. Another good source for military recruits - many sign up to avoid the harsh environment or receive better pay.

!!![[TheFinalFrontier New World]]

Planet that is newly discovered and open for grabs. Expect [[DeterminedHomesteader new settlers]] or folks fighting over the planet. Such worlds would have little to export and much to import, due to a lack of infrastructure. If settled, frontier towns are likely. Local government is minimal at best. Because of the lack of infrastructure, these new colonies tend to be [[EasilyConqueredWorld easily conquered]].


Dumping grounds for "discontents". Expect these worlds to be unpleasant at the very least. Can range from orderly communities to work camps to lawless wastelands. If these worlds export anything, it's products of slave labor. If governed, it would be by the prison administration (authoritarian by necessity).


Places for tourists to visit and relax, often paradise worlds or something akin to Las Vegas in space. Mostly, it is [[VacationEpisode a place for the protagonists to relax]], especially if there's [[BeachEpisode beaches]]. Not likely to be a major target, unless it's a strategic location or [[FriendlyTarget attacked for symbolic reasons]].


Known for its [[ForScience research and development]], and its state-of-the-art technology. The natives [[TheSpock value logic]] and ruled by technocrats. Home to a lot of [[RuleOfCool cool gadgets]], [[FuturisticTechIndex new technology]], and [[GadgeteerGenius various scientists]] ([[MadScientist mad]] or [[ScienceHero otherwise]]).

Instead of production, these worlds focus on training and providing professionals. Common in [=SF=] are:
##Medical: Devoted to healing others in body and mind. Includes Doctors and Psychologists.
##Education: Known for their universities and training centers.
##[[MerchantCity Financial]]: People who work with money, including loaning, banking, trading, escrow agencies, etc. Often ruled by {{Merchant Prince}}s.
##Military Support: The supreme headquarters of the armed forces, academy for the fleet's officers, and boot camp for the army's troopers.
Other services can include lawyers, intelligence agents, engineers, beauticians, etc. May also produce items of great importance to these services, such as instruments if the planet is known for its musicians.


Places to build spacecraft. Since ships are vital to an interstellar empire, the yards are vital industries and military assets. Often military/government operated.

!!![[WretchedHive Underworlds]]

Planet notable for its black market products and services. With enough money, one can hire [[{{Criminals}} thieves, smugglers, and assassins]]. Otherwise, one can purchase slaves, illegal technology, and other contraband. The items provided by an Underworld need not be illegal, but merely taboo. Such locations are commonly seedy and [[TheOmniscientCouncilOfVagueness ruled by those in the shadows]].

[[folder: Unique Locations]]

Artifact of {{Precursors}}, often a massive construct such as a DysonSphere or [[RingWorldPlanet ringworld]]. Or recently made by a highly advanced civilization. Can be visited by [[AdventurerArchaeologist intrepid explorers]] and researchers to produce LostTechnology. There is a disturbing trend for BDO's to be [[AbandonedLaboratory abandoned]], acting as [[SealedEvilInACan prisons]] for [[TheVirus alien viruses]], which are accidentally released by said explorers.


Structure that houses a huge database of the knowledge of an entire civilization. Many researchers visit here to learn from the accumulated knowledge. Often left behind by Precursors, though such projects are undertaken by more recent societies as a prestigious project. Expect it to be [[SpookySilentLibrary very quiet and vast]], and attracts [[SeekerArchetype seekers of truth]].

!!!Phlebotinum Monopoly

When there's only one source of Immortality Drugs, Dilithium Crystals or Spice, and everybody needs it. Whoever controls this world can control the galaxy. Anticipate this world to warrant fleets or warships and armies to protect it, and [[NoBloodForPhlebotinum many fights over it]].


Where a [[WeaponOfMassDestruction Weapon of Really Mass Destruction]] is housed. Whoever controls the superweapon can decide the fate of the galaxy. In SpaceOpera, this is the site of a [[FinalBattle climactic battle]].

[[folder: Statuses]]
In addition to the above types, there are several attributes that can affect the value of a world. Some may overlap or change over time, depending on the current situation.


Worlds or stations inhabited by Intelligent Extra-terrestrials. An important term for emerging space societies or [[InvisibleAliens where life is rare]]. Trade and travel depends on the temperament on the aliens.


Prohibited from trade, frequently with an enemy fleet enforcing the embargo. Smugglers and rebels would try to get pass the blockade for various reasons. Such embargoes continue until the political situation changes.


Trade hub, either acting as a key location on HyperspaceLanes or housing the headquarters of one or more major corporations. Mercenaries and private security forces will maintain order. The destination of many {{Intrepid Merchant}}s, but possibly plagued by [[SpacePirates piracy]].

!!!Cultural Hub

Major center of [[{{Art}} arts]] and learning, valued for its impact on society. Often focused on entertainment or academics, these tend to be ruled by open and free societies. The destination and home of artists, musicians, students, writers, and and other creative folks. Tourists are also common, which also means {{Street Performer}}s are near.


Technology or infrastructure is lagging. Part of the Interstellar culture and trade, but often less advanced than the major powers. Except these planets to be impoverished, often new colonies or exploited conquests. Between the major powers, [[SpaceColdWar the Developing worlds would be caught between political struggles]].

!!![[AfterTheEnd Dying]]

[[TheEndOfTheWorldAsWeKnowIt Has seen better days]], and is now waning. They may have been over exploited and depleted of primary resources or undergoing a natural calamity. To escape their fate, refugees will flee to the stars. These planets tend to collect garbage, [[ScavengerWorld both physical artifacts and the seedier elements of society]]. If anything of worth remains, it's related to the planet's primary export.


Can support human life, or whatever species the protagonists are. Can range from Edens to barely habitable {{Death World}}s. In a setting were most planets are dead or uninhabitable (say RealLife), a planet with a breathable atmosphere is better than nothing.


Were a species originated from. A lot of historical and religious importance, because of its mystique of being where a species is born. The dominant species of an Empire will have their homeworld as a Primary Capital, although there are exceptions. The destruction of a Homeworld is often a major mistake for space tyrants: it not only crosses the line, but [[GenocideBackfire ensures that a native of that world would eventually destroy said tyrant]].


Location of past importance, such as a battle or discovery. Often archaeological sites or monuments are located here. Because of this status, these places are seen as important symbols. For example: a dead moon may have little or no value, but military commanders may make choose to fight there since it was the site of a previous victory.

!!![[HolyCity Holy Center]]

Place of major importance to a religion, with many places of worship and pilgrims. If the religion is benign, attacking this center is a sign that you're an evil jackass. More fanatical sects would protect these centers. May be governed by a Theocracy, though it depends on the faith.

!!![[LostColony Lost]]

Location is no longer accessible or has disappeared. This could be due to a variety of reasons: The local Gate has been destroyed, the wormhole that connected the location is now unstable, or ''something'' happened to the settlers. In either case, no one knows were it is and may become myth. Explorers may find these places again.


Location that akes no sides in a conflict, either [[TheNeutralZone forbidding]] sides from entering with force or acting as a [[TruceZone third-party mediator]]. Generally worlds or stations that have little interest in fighting, but plenty of services to offer (shipyards, underworlds, pleasure planets, etc.). Often well prepared to make sure they maintain their neutrality.


Little or no high technology or advancements. Any inhabitants are either aliens developing civilization or the remnants of a failed colony, [[BarbarianTribe often savage]]. Expect wilderness and perhaps alien ruins. Any interest to these worlds are either for Science or Strategic. Travel to such worlds may be restricted, as to avoid exploitation or culture shock.


Travel to and from location restricted due to a medical emergency. A temporary measure until a cure can be found for the ailment, if at all. Except for medical craft and warships, no sane being would risk going lest they too fall victim. If the plague is left unchecked, the quarantined world may become permanently Forbidden. If it gets really bad, [[QuarantineWithExtremePrejudice the planet may be sterilized]].


Location makes this world a vital military target. Expect military fleets and fortresses here. With changes in warfare, space travel, and the political environment, a location could cease being a military prize.


The local political situation is bad, and society is barely holding together. Order can fall apart at a moment's notice. Merchants and travelers will avoid going there if they can help it. It results in less trade, and could lose its status as a trade or culture hub. If it's really bad, it may become a War zone or worse.


Location is the center of an armed conflict, with military ships and troops fighting each other. Mercenaries and arms dealers would be attracted to this place. Lost of life and destruction of infrastructure will negatively impact its value. Refugees from this world would be common. If this status lasts long enough, a planet may become Dying as well.




[[folder: Anime and Manga]]
* ''LightNovel/CrestOfTheStars'': Interstellar travel relies heavily on Gates. During Jinto's and Lafiel's adventures, they visit a Factory asteroid (producing Antimatter) and a Strategic planet, help enforce a planetary Blockade, and later come across a rather civilized Penal world.
* ''Anime/MobileSuitGundamSEED'': ZAFT's colonies were arranged in this manner, with one group focusing on Farming, another on Information Science, another on Chemistry, and so on.

*''Film/{{Avatar}}'': An example of interstellar commerce with STL craft. Pandora is mostly valued for its Phlebotinum Monopoly, though it has an Exotic Alien society and ecosystem.
* ''StarWars'': As with any good space opera, Star Wars provides plenty of examples. Coruscant is a Capital, Bespin and Kessel are Mines, Endor houses a Superweapon, the Death Stars and Starkiller Base ''were'' Superweapons, Geonosis is a Factory world, Tatooine is a minor Underworld, and Yavin and Hoth were strategic locations. Naboo was Blockaded for a while.
** Numerous worlds, such as Naboo, Geonosis or Kamino, were Homeworlds for various alien species.
* Spoofed in ''Film/StingraySam'' with Durango, a Planet of Rocket Builders which after an economic slump turns into a Planet of Criminals and then a Planet of Prison Factories (in which they build rockets).

* ''Literature/ChildeCycle'' by Creator/GordonRDickson: The interstellar economy depends on specialized services, almost to the point of CripplingOverspecialization. Dorsai and the Friendlies provide Military, Ste. Marie focuses on Farming, the Exotics on Health Services, Coby on Mining, Newton and Venus on Science, Ceta on Commercial Services, Cassdia on providing Technical Services as well as mercs. Zombri, otherwise an uninhabited world, is a Strategic location.
* Parodied in "The Didactics of Mystique" by "Flash Richardson" (Grant D. Callin).[[note]]The title is a takeoff on the Childe Cycle novel ''Tactics of Mistake''[[/note]] Interstellar civilization is falling apart because each world offers only one profession, and there are far less inhabited worlds than needed professions.
* ''Literature/CoDominium'': Alderson Points serve as Gates. During the [=CoDO=] era, most worlds were used as Mines, Drug Farms, and Penal Colonies. Many industrialized worlds hired out Military forces as mercs. Latter, more examples, such as Pleasure and Alien worlds begin to appear.
* ''Literature/ConSentiency'': With the development of Jumpdoors (acting as Gates), traveling between the stars is so causal there a planet devoted to a single service: Beautician worlds, Honeymoon Worlds, even Gynecologist Worlds. Dosadi is part Penal and part Science World, where every inhabitant is part of a massive experiment.
* ''Creator/CordwainerSmith'': In his Instrumentality milieu, Norstrilia is a Farm World with a Phlebotinum Monopoly, making it extremely rich and envied. Viola Siderea is an Underworld, a planet of thieves. Shayol serves as a Penal world of the BodyHorror kind.
* ''Franchise/{{Dune}}'': the eponymous planet is a Phlebotinum Monopoly, with Giedi Prime a Factory world, Ix and Richese are Science worlds, Tleilax is a Biological Science world, Caladan is noted for Farming and Fishing, Kaitain is the Capital, Salusa Secundus is ostensibly a Penal colony but also a Military world. Tupile is a Service world, providing protection for exiled families.
** Ginaz is a Military world, training swordmasters for the various Houses. Swordmasters of Ginaz were instrumental during the Butlerian Jihad.
* ''Literature/{{Foundation}}'': Trantor is the Capital, Terminus serves as Science/Library as well as another Capital. Many other planets are Developing/Strategic due to their location and influence, as well as Mines. Pleasure and Farm worlds are also mentioned.
** This varies through the series. At the beginning, Trantor is a CityPlanet which essentially produces government and nothing else, while Terminus initially exists to produce an encyclopedia. Later on after the collapse of the empire and rise of the Foundation, Trantor has become a largely rural planet with no products to speak of [[spoiler: other than the psychics who secretly run everything]] while Terminus has become a much more rounded capital planet. It's implied, although never really explored by the books, that other planets must also have become more balanced; the farm worlds which used to supply Trantor with food no longer having anywhere to export their produce to, for example.
* ''Literature/GauntsGhosts'': The forest planet Tanith was, when it still existed, a major exporter of high-quality wood.
* ''Literature/HammersSlammers'': Several Farms and Mining Worlds were apparently set up this way so new colonies couldn't become economically independent. Occasionally, the protagonists end up fighting in Big Dumb Objects or against Aliens.
* ''Literature/TheHitchhikersGuideToTheGalaxy'', to the point that some planets now have commodities growing naturally on them such as a swamp planet with mattresses that get slaughtered and dried to be slept on. Another planet has tools [[GrowsOnTrees that grow on trees.]]
* ''Literature/TheHungerGames'': Districts in the series function like this. Each has one and only one job to do (such as District 12: coal mining, or District 11: agriculture), all of which support the Capitol.
* ''Literature/APlanetCalledTreason'': Variant of this trope on a planetary level, where each Region on the planet are Service providers, specializing in different areas: Biology, Theology, Genetic Engineering, and Acting, to name a few.
* In ''Literature/HonorHarrington'', The Manticore System serves as a Gate, housing the Manticore Wormhole Junction which provides Manticore with a lot of economic clout.
** Montana's only significant export is stated to be beef, and it is frequently suggested that Montanan beef would command top prices on developed planets in the League or SKM. That said, one wonders how many cows it takes to fill a five ''million'' ton freighter...
** During the war with Haven Trevor's Star serves as Strategic since its holds a Junction Terminus that would allow Haven access to the Manitcore system. It's also becoming the Capital World of the burgeoning Star Empire of Manticore.
** Beowulf in Sigma Draconis is a Science World, noted for being the galaxy wide leader in (ethical) biomedical and genetic research. Given recent developments in the series, it may also become Strategic as well since if also hosts the one end of the Manticore Wormhole.
* ''Literature/{{Retief}}'' has the CDT sent on various Alien/Developing worlds, often trying negotiate with the natives. Such worlds are often caught between the cold war of the CDT and the Groaci, who vie for political influence.
* In the ''Literature/VorkosiganSaga'', Komarr serves as both Gate and Strategic for Barrayar since it contains the wormhole route that is the ''only'' connection that Barrayar has to the rest of the galaxy. The Hegen Hub is a more general Gate. Beta Colony is Science (of almost all varieties), Jackson's Whole is Underworld Service and Earth is Cultural Capital.
* Sometimes the specialization is stated more in terms of species than of planets. In Star Guard by Creator/AndreNorton, Earth, a poor backwater latecomer to a galactic civilization, exports soldiers for combat on primitive or more advanced worlds (the military units are referred to as "Archs" and "Mechs" respectively). In Alan Nourse's Star Surgeon, each species has a specialty, and Earth's is medicine; this sets up a story in which the hero is a nonterrestrial doctor who faces prejudice in his attempt to succeed in the Terran-monopolized interstellar medical system.
* Dirigent in the ''Literature/DirigentMercenaryCorps'' series has its entire economy organized around supplying two things: [[PrivateMilitaryContractors Professional soldiers-for-hire]], and weapons.
* An InvokedTrope in Creator/HarryHarrison's ''To The Stars'' trilogy, which has a Big Brother-like Earth lording it over interstellar colonies set up to be totally dependent upon each other. Since each colony requires numerous goods (which they are never allowed to stockpile) each made only on one of the other colonies, it would be impossible for a revolt to succeed unless every colony did so at once. [[TheWarOfEarthlyAggression Which they do.]] Not only are the planets set up this way, but their cultures are also custom-designed to reinforce this setup.
* In ''Literature/EmpireStar'' by Creator/SamuelRDelany, Comet Jo's homeworld exists only to produce a plant called plyasil. Everyone living on the planet is either involved in plyasil production or in supporting the people who produce the plyasil.

[[folder: Live-Action TV ]]
* ''Series/{{Andromeda}}'' has several prison planets and a planetary system that accepts garbage from other systems.
* ''Series/BabylonFive'': There is a brief mention of a Disneyplanet, and the Centauri Republic colony world of Ragesh 3 is identified in discussions as an agricultural colony.
* ''Series/BattlestarGalactica2003'' had the Twelve Colonies of Kobol set up as such. Aerilon was the "bread basket" of the colonies. Caprica was the capital and cultural Center. Gemenon is a holy center. Libran is known for its lawyers. Picon has strategic value (the Fleet HQ was located here), and a cultural center since it was used as a [[StargateCity substitute for Caprica in entertainment]]. Scorpia had shipyards, and Tauron was another farm center.
** Following the fall of the colonies, the rag-tag fleet's economy is set up like this. Justified, in that only certain surviving ships were only equipped for certain functions.
* ''Series/DoctorWho'' has featured many such examples. "Silence in the Library" takes place on a library planet. Satellite 5 is a Service station providing news [[spoiler: and a Capital for the true rulers of the Human Empire]]. Billions of Years in the Future, Earth is a Cultural and Historical Center.
* An early episode of ''Series/{{Farscape}}'' deconstructs this trope: Sykar was forcibly remade into a farm world by the Peacekeepers; most native plantlife was almost completely destroyed to make way for vast fields of Tannot root, and every single inhabitant of the planet were reduced to farm-labourers, planting, tending and harvesting the crops. Thanks to the high demand for Tannot root, the farms themselves are steadily being worn out through overharvesting and reduced to barren wastes; the one seen in the episode is said to be the last fertile region of the planet. For good measure, the only thing stopping the Sykarans from noticing any of this is the fact that their food is made entirely of mind-control drugs, and they all believe that ''every day'' is the last day before a weekend.
* ''Series/StargateSG1'': Most worlds are valued as Mines for rare materials, although Libraries, Big Dumb Objects, Farm worlds, Forbidden worlds, and Superweapons make appearances.
* ''Franchise/StarTrek'': Earth serves as the Capital, though oddly enough unprotected in many movies. It, along with Mars, also has Shipyards. Risa is a Pleasure Planet, Rura Pente is a penal world, and there are various {{Unobtainium}} mines, Big Dumb Objects, Forbidden locations, and Exotic places. Memory Alpha was a Library world for the Federation, though we only saw it during construction.
** ''Series/StarTrekTheNextGeneration'' shows us the trope in action. In the episode "Symbiosis", one of the two planets of the week produces nothing but a narcotic which the other planet believes is a cure to a virulent plague (whose symptoms just happen to look exactly like withdrawal). Deconstructed -- the providing planet ''used'' to have a broader commercial base (it was the poorer and less developed of the pair, but still a full civilization), but the profits of the drug were tempting enough that gradually other industries fell out of use over the generations until ''both'' sides were effectively addicted -- the buying planet literally, and the selling planet by being dependent on selling the narcotic to keep society running. The system ultimately collapsed when their technology regressed to the point that they couldn't maintain their spaceships (and the Enterprise declined to enable them by fixing them).

[[folder:Tabletop Games]]
* ''TabletopGame/FadingSuns'': Uses the trope, with many different examples. For instance "Urth" is the Holy center of the Urth Orthodox church while the Imperial Capital of Byzantium Secundus is a Gate nexus.
* ''TabletopGame/{{Warhammer 40000}}'': Many worlds are known for what they produce to feed to the Imperium's war machine, with Forge worlds producing complex technology from materials supplied by Mines, Agriworlds producing food for [[CityPlanet Hive worlds]], Hive, Knight, Feral and Death worlds providing different kinds of Military forces, Holy Terra being both a holy Capital of the Imperium and the human Homeworld, and Cadia being a Strategic world. [[CrapsackWorld Needless to say]], most worlds serve as [[ForeverWar settings for War]] at one point or another.
** Hive worlds supposedly produce a lot of different products, although they're best known as a source of CannonFodder for the Imperial Guard.
** Numerous Shrine Worlds besides Terra serve as Religious Centers.
** Feudal and Feral Worlds are Primitive, being former colony worlds which regressed to either agricultural or stone-age levels.
** Numerous Lost human colonies exist, most dating back to the Dark Age of Technology, which are found and incorporated into the Imperium from time to time.
** Numerous planets on the Imperium's frontier, where the Imperial law isn't fully settled in, act as New worlds.
** Various worlds are Quarantined by the Imperium for a number of reasons, ranging from Chaos or Necron outbreaks to matters of Imperial security.
** Many worlds are under the control of aliens, chiefly Eldar, Tau, Necrons or Orks.
** T'au serves as both the Capital of the Tau Empire and the Homeworld of the Tau species. Also within the Tau empire are Pech and Vespid, the Homeworlds of the Kroot and Vespid species.
* Zig-zagged in ''TabletopGame/{{Traveller}}'', planets have trade codes similar to the categories listed above, but most export more than one product.

[[folder:Video Games]]
* ''VideoGame/WingCommanderPrivateer'' put the player in the shoes of a freelance ship owner during a peaceful period of the Terran Confederacy's reign. While the most obvious route to take was killing anything that shot at you, it was entirely possible to make a living solely from trading between the planets, each of which had a specialty. Due to this, each planet would produce certain goods cheaper than elsewhere and purchase some goods for more than other planets.
* ''VideoGame/EVEOnline'' usually subverts this, there are usually a wide variety of goods available at a given market.
** while this is true for the stations in the orbits, with the planetary interactions and the general SingleBiomePlanet, many players play this straight: get a temperate planet as factory world to make tier 3 or 4 products, while the other planet types often make mine worlds to get the supply for the temperate one.
** Also about the moons, as you can only have only one POS (Player Owned Station) in their orbit: some are deathstars loaded with weapons, others have factories or science facilites, and others are just there to mine the moon if it holds valuable resources.
* Mostly averted in the ''VideoGame/{{X}}-Universe'' games, but some sectors specialize in only a few types of goods. Asteroid Belt in ''Terran Conflict'' mostly produces different types of minerals from the asteroid mines, for example. Because the X-Universe is a TerminallyDependentSociety that relies on the PortalNetwork, numerous one product planets face societal or biosphere collapse when the jumpgate network shut down ("The Dark") following the apocalyptic Second Terraformer War. In ''Videogame/XRebirth'', [=DeVries=] is one such system, being an Earth State mining outpost that relied heavily on tech and food imports; when the network collapsed about 30 years ago, the colony faced mass famine and [[LostTechnology technological decline]], and has only recently started to recover.
* Partial example in the ''VideoGame/EscapeVelocity'' series, where bulk commodities can be purchased at most worlds. Usually, among the generics (food, metals, equipment, luxuries, medical supplies) one or two will be cheaply available and one or two will be more expensive. However, in ''Nova'', many worlds have a "special" commodity that is generally only traded at two or three worlds (some supplying it, others demanding it), which are either valuable or just interesting flavor.
* In the ''VideoGame/{{Myst}}''/''VideoGame/{{Uru}}'' franchise, many Ages served a single economic or social function, often quite narrow. For example, the Age of Teledahn was farmed for a type of fungal spore used in D'ni cuisine.
* ''VideoGame/KnightsOfTheOldRepublic'' features Manaan, an ocean planet that is the Galaxy's sole source of the medical substance called "kolto" (the naturally produced precursor to the synthetic bacta from the movies).
* ''VideoGame/StarWarsTheOldRepublic'' features this with Quesh. The ''one'' reason the Empire and the Republic are interested in this planet? The Quesh Venom can be refined into useful adrenals. This is also the only reason that the Hutt Cartel is expressing any interest in the planet as well.
* ''VideoGame/ScrapMechanic'' is set on a dedicated agricultural planet, staffed primarily by robots to reduce costs and the need for human presence. [[TurnedAgainstTheirMasters One can guess where that eventually went]].

[[folder: Western Animation]]
* ''WesternAnimation/InvaderZim'': The Irken Empire from Invader Zim has conquered numerous alien planets to give them a convenient specialization. Some examples: Blorch, the new parking structure planet; Callnowia, the mail order planet, along with Conveyor Belt Planet for shipping; Conventia, the convention hall planet; [[ExactlyWhatItSaysOnTheTin Foodcourtia]], the food court planet; etc. They have so many they don't even really have a plan for new planets until they conquer them and wipe out the lifeforms present, then they just decide on a whim what kind of new planet might be handy or fun.
* In ''WesternAnimation/ShadowRaiders'' the four planets of the Cluster--Fire, Ice, Rock, and Bone--each have one resource that the others need, although at the start of the series they've been raiding each other for years instead of trading.