In the vast majority of inhabited systems, stations are the main type of human habitats. Modular, adaptable, easier to access than ground settlements and sometimes even mobile, stations house dozens of millions of people across Communal Space. Though very diverse in terms of construction and inhabitants, space stations in inhabited space can often fall under several distinct types which are displayed in the following entry. 

/ZANZIBAR STATIONS

The Zanzibar model of stations was originally developed by the African-European Space Agency and later on upgraded by the Moon Communes as human presence in low earth orbit kept increasing at the end of the Low Age. It follows the model proposed in 1929 by John Desmond Bernal. The centre of Zanzibar stations is a hollow, rotating spherical shell housing habitation and agricultural facilities in low to medium gravity. From this spherical core, Zanzibar-class stations may extend through additional agricultural rings, docking facilities or zero-g factories. Capable of housing up to fifty thousand people in rather good if urban conditions, Zanzibar stations are most often used as supporting space stations in heavily settled systems. In low-population systems, however, a Zanzibar station might be the main settlement. In Communal Space maps, Zanzibar stations are almost always referenced through their economic specialization, which is reflected in their names, such as Evergreen, Forge, Shipyard or Granary. Zanzibar stations are almost always associated with a planetary body and "free-floating" Zanzibar-class stations are relatively rare.

A variant of Zanzibar stations called "Hollow Zanzibar" can be found as hollowed-out asteroids, generally in asteroid belts or gas giant rings.

/BABYLON STATIONS

The Babylon blueprint was first designed by the Moon Communes but the rights are currently in a legal void due to a conflict with the Giants' Collective, meaning Babylon Stations are de facto public domain designs. It is based on Gerard O'Neill's design from 1976: a vast inhabited station made of two counter-rotating cylinders providing artificial gravity via centrifugal force. The cylinders are connected at each end by a rod via a bearing system, creating a vast structure that can be anywhere between 30 and 100 kilometres long. The inside atmosphere is at a breathable pressure and provides adequate shielding against cosmic rays, as well as an inner weather system for the cylinder. Vast transparent sections, as well as mirrors, reflect light from the parent star of the cylinder. Babylon stations are truly massive achievements, often taking decades to build and mobilizing the resources of entire planetary cooperatives. The decision to build one is often linked to the necessity to have non-planetary population centres in a system, either due to the absence of an earth-like world or the fear that active colonization might destabilize the ecosystem of an existing world. With populations numbering in the millions, Babylon stations are more often than not independent polities and in Eloran space harbour their qith or cooperative syndicate. Babylon stations are often named after the various ecosystems they contain: they are spacious enough to have diverse biomes ranging from forests to small seas, offering living conditions similar to planetary surfaces.

/CATHEDRAL STATIONS

In her seminal study of the geometry drive, Rani Spengler stated that there was no apparent theoretical limit to the size and mass of objects displaced via a geometry translation. Cathedral stations seem to have been created with the sole intent of testing this theory. Almost functionally similar to Babylon stations albeit at the lower end of the scale in terms of size, Cathedral stations are O'Neill cylinders with interstellar capacities provided by a station-sized geometry drive installed at the non-sun-facing side of the cylinder and powered by a station-wide computer network. The presence of such a massive drive creates a side effect that makes a Cathedral station translation a very rare and peculiar occurrence. The station is so massive that its translation creates spacetime disturbances at the arrival point called "weaves" which can hamper translations all across a system for days as they propagate at the speed of light. As they are devoid of sublight propulsion except for basic altitude control, Cathedral stations require towing ships to stabilize at their desired locations. With their geometry drive accounting for 80% of their cost, Cathedral stations are extremely expensive and very rare with only five occurrences across settled space.

The most well-known Cathedral stations are the Irenian stations that colonized the Pleiades, such as Phi Clio. 

/SUNFLOWER STATIONS

Sunflower stations are the most recent station type in settled space and the only kind whose designs aren't clearly open-source - the copyright older is qith Saïmour in Eloran space, though they are notoriously sloppy in enforcing it. Sunflowers can be understood as a middle ground between Zanzibars and Babylons: they take the somewhat small size of the former and Earth-like environment of the latter, combining them in medium-sized circular stations with a rotating outer habitation ring and an inner utility ring, all attached to a central docking module. Sunflowers are practical, elegant but expensive - in no small part because they cannot retain their atmosphere which requires the outer ring to be encased in a band of transparent material. Sometimes derided as vanity projects for rich communes, Sunflowers are generally found in planetary orbit and are mostly built by communes rich enough to upgrade their Zanzibars and not willing to seek out the partnerships required to build Babylons. For this reason, Sunflowers are most commonly found in independent, isolated systems.

/WAYSTATIONS

Waystations are not really a class in and of themselves - they're a use case, not a specific blueprint. These small stations house AI systems and at best a few dozen people. They are present in systems devoid of any other human presence but that are part of long-range interstellar routes. Their main function is to provide external computing capabilities for small ships, thus increasing their effective range, but waystations also provide typical relay services like refuelling, emergency repairs and medical attention. They also handle interstellar communications by allowing courier drones to resupply and computing their jumps to the next waystation in their route. The vast majority of relays are under the authority of either the Moon Communes or Eloran qiths, however, there are potentially hundreds if not thousands of unregistered, independent or dormant waystations outside of officially settled space.

I have been unable to find the source for illustration: Cathedral Station. Sunflower Illustration: Elysium, Neil Bloomkamp (director).