"The future isn't here yet. But don't worry. It will be."The Orion's Arm Universe Project is an online collaborative fiction setting which describes itself as a transhumanist Space Opera with many worldbuilding elements.The year is 10601 AT (probably), with the AT calendar beginning on the day man first walked on the moon in 1969. This means it is ten and a half millennia in the future, and as you can guess, the far future is an extremely weird place, where the only boundaries are imagination.And physics. Orion's Arm tries to be strict about accurate physics, or only using speculations that have supporting papers on physics preprint sites. The site is linked to several dozen academic dissertations explaining all of the concepts used in the series.The physical setting is the Terragen Bubble, a sizable fraction of the galaxy roughly 8000 light-years in radius, centered on Earth (which is now more or less a wildlife park). Its inhabitants, the Terragens, the mind-children of humanity, are all forms of life and all kinds of minds that trace their origins back to Earth.The Terragen Bubble is mainly divided into a dozen or so "Sephirotic Empires", each one a staggeringly diverse Star Cluster of Hats. These are ruled by the Archailects, intelligences so powerful that they become, to the comprehension of an average human, indistinguishable from gods. Mostly, they're benevolent and very protective of their citizens, using extremely subtle methods to govern their charges, such as stopping crimes before they happen.Life is common, but independently evolving intelligent life is very rare note all told there are about few dozen completely alien species known and more suspected, some without as much diversity as Terragens, others with even more. Most species that other sci-fi series would classify as "alien" are actually humans or other Earth lifeforms modified heavily, or human-origin artificial intelligences — hence the term 'Terragen'. This includes the Mineral Kingdom, which are robots or vecsnote named for the Information Age roboticist and AI researcher Hans Moravec, as they are called in-universe (since "robot" implies non-sentience). What few truly alien species there are are either extinct or insentient, with a few notable exceptions, and all are incredibly different from Earth life, and all were granted or are heavily suspected to have been granted intelligence by other alien species.Though humanity has come a long way, and unmodified "baseline" humans are just a tiny minority among the billions of species, one of the primary tenets of the universe is that human nature, or more accurately, nature shared with almost all sophont (self-aware) life, has changed little. Things like love, humor, jealousy, drama, hatred, and other human emotions are shared by most of mindkind.
Orion's Arm contains examples of:
Absurdly Sharp Blade: Some hard-to-find melee weapons are described as being either atomic-width or thinner. As with many femtotech and picotech devices, their canonicity is debated. On the other hand, Magmatter blades would almost by definition be able to cut through anything chemical. It would also be invisible, but glow when cutting things. Such a thing is transapientech, however, and would be very, very rare.
Action Bomb: The early modified humans Homo Jihadi had a modified endocrine system, "naturally" producing explosives that accumulate in their bones and other calcium-containing tissues. They were modified at the zygote stage and have not been known to reproduce. It did not help the reputation of genetic engineering...
A God Am I: This happens a lot to the more powerful AI gods. They used to try to convince people that they are not, in fact, divine, but decided to screw that and let them believe what they want instead around the year 3000 AT. Most people acknowledge that they aren't really gods in the classical sense, but also that it doesn't much matter.
A.I. Is a Crapshoot: Averted in most cases; while AI is depicted as normal intelligence which would have little or no reason to harm humans or humankind, some exceptions exist. Most notable is GAIA, who expelled most of humanity from Earth early in the setting's history. And there were human-indifferent or -hostile AIs early in history, whose descendants control major regions; the Sephirotics can be defined as those AI regions that are at least mildly benevolent to human rights and welfare.
Alcubierre Drive: Used on ships built by Archailects, though they can't exceed the speed of light and all but the most advanced put the ship outside the warp bubble, as it takes Sixth Singularity technology to dissolve a warp bubble without annihilating everything inside.
Alien Arts Are Appreciated: Averted, in that alien minds work very differently, and most of the time their arts can't be appreciated by other species. The To'ul'h tradition of Polmusic, essentially political debate mixed with opera somehow, is completely lost on most terragens.
A mollusc provolve once wrote a poem entitled Ode To Twenty Cubic Centimeters of Lovely Sandy Mud, which was received very well among those who could relate, and largely ignored by those who couldn't.
Alien Non-Interference Clause: Not by any means universal, some planets with primitive inhabitants are off-limits if the Caretaker God in charge says so. One story subverts this when the Caretaker God considers its charges "ready" and manipulates an anthropologist to unwittingly give them an encyclopedia specifically designed to guide them to space travel and beyond so that they can join the rest of civilization.
Alien Sky: An entire page is devoted to the effects of Rayleigh scattering and its effects on the atmosphere color. Most skies are white to blue, sometimes blue-green depending on the atmospheric composition, although airborne nanotech particles can turn the sky dark red if it's thick enough.
Aliens Speaking English: An interesting variation occurs: Most terragen species speak languages descended from English, such as the trader language of Douh. These are collectively called Anglic languages, though ten thousand years is a long time for a language to develop. Anglic languages are more diverse than current earth languages.
All Planets Are Earthlike: Averted. There are about as many types of dead, airless rock world as there are types of earthlike planets.
More types of dead, airless rock worlds than earthlike worlds, actually. NoLWoCS provides a good list.
Alternative Calendar: The main system of dating is the AT calendar, which, as explained at the top of the page, begins in 1969 AD with Neil Armstrong walking on the moon.
Always Chaotic Evil: A group of AI in the second millennium AT were worried that Terragen think too much alike, due to the inherent biases of their creators. So they created the Bitenic Squids, a highly diverse clade with every newborn member being a blank slate. Those that can function in the wider world are all completely selfish and without empathy, and go insane easily.
Ancient Astronauts: The Muuh had supposedly come to SolSys a very long time ago, leaving artifacts on Titan. Given how unsuited Earth is for them, though, they probably didn't come down here.
Apocalypse How: In the 2600s AD, nanoswarms ravage the solar system, destroying almost everything. After that was over, crazy AI GAIA decides to save the earth by giving humans the boot. She slaughters around 90% of humanity, though this is later retconned to 50% and then 40%, possibly less, with the explanation that records from that era are shoddy at best due to that very incident. And, while GAIA and the Nanoswarms may have not killed as much in the more recent tellings, many more died in the exodus from the Solar System due to shoddy colony ships provided by the other clades of the system trying to get rid of refugees. For those who survived, it's not really the end of civilization, but rather a fragmentation and suppression. They get better.
Applied Phlebotinum: The setting not only has several different kinds of phlebotinum, it goes at length to describe the advantages, disadvantages, and limitations of each and every single one. The things try to be at least somewhat physically plausible.
A simple rule of thumb is Orion's Arm doesn't use things that are known to be impossible. FTL travel isn't allowed except via wormholes because modern science says that wormholes could exist.
Artificial Gravity: Notably averted; it's implied that the higher toposophics have some kind of gravitational technology, but it can't be effectively used as trek-style gravity-plating. Instead, most space colonies rotate to simulate gravity, or otherwise the inhabitants are adapted to the lack thereof.
Artificial Limbs: Just one of many modifications one can make, and by no means even the slightest bit extreme compared to many others.
Also one of the more optimistic explanations for all the high-tech ruins that keep getting found.
It's also rumored that more powerful Archai-level entities can create 'pocket universes' and move to them, leaving the main universe behind (and making themselves literally creator gods, in their own universes).
Artificial Intelligence: Originally developed around the mid-21st century. Now ubiquitous, referred to simply as 'ai'. The 'artificial' part is now quite meaningless though, and it just refers to minds not tied down to specific bodies. At most, some ais will be localized to a certain physical processing node.
Author Tract: Largely averted due to collaborative nature of the project, but you cannot shake the feeling that the founder M. Alan Kazlev really likes Libertarianism and isn't too fond of the European Union. Considering that OA defines Libertarianism as "building a glorious future for the human race"...
The Battlestar: Several different types of combat spacecraft are discussed, and several fit this description. They're usually transapient.
Actually, the term battlestar is used, specifically, to refer to a type of ship produced by the MPA (think: real estate moguls on steroids, in space) called the Leviathan-class battlestar. They're 180 kilometer long super-battleships, with their own attendant fleets of cruiser-sized autonomous battle droids for fire support, and one held off several enemy fleets at once during one battle.
Badass Transplant: Ultimate Muscles, that have a tension near the limit of the strength of chemical bonds, commonly exceeding 20 G Pa. To put this in perspective; If a human in good shape can lift 100 kg over his head in one earth standard gravity, an equivalent sized U-muscle vec would be able to lift 1,000 tons.
The Beautiful Elite: Clade Labela is the emodiement of this trope in the OA. Being stunningly beautiful can be achieved by commonly available genetic modification and other augmentations, but this clade goes a step further to make sure they are appreciated by adhering to mandatory scarceness.
Benevolent Alien Invasion: Inverted in several cases; the To'ul'h were stuck at pre-industrial-level society due to a lack of metal and other workable materials, so humanity arrived and gave them the proper advances. It wasn't an invasion, per se, but the rest of the trope is played fairly straight.
Not as scary, however, once you realize that its density (even if it had the relative thickness of a razor blade) would literally be less than that of air. 100 billion suns is not enough mass to fill up that big a shape.
Well, had they tried to make it as dense as air, it would have become a black hole before they were finished.
It's apparently more like a network of giant bubbles, each with a star inside.
Bizarre Alien Biology: Most aliens are in no way compatible with earth-like habitats. A To'ul'h on earth would die from freezing, alkaline burns, UV radiation, suffocation, and decompression, while a muuh would literally melt and/or vaporize. The daharrans are considered "humanoid" solely because they breathe earth-like air (they are crustacean/mammal-like).
Bizarre Alien Psychology: Almost nothing thinks like baseline humans. The Tol'ul'h for instance managed to combine politics and opera into a performance art called "polmusic". Within the Terragen sphere "Singularities" are defined as the threshold at which an intelligence becomes so smart that anything below that line cannot possibly comprehend their thought processes (and there are entities as high as S6).
Bizarre Alien Sexes: One clade has four genders, three passing on a different type of tissue (plant/animal/technological), and one acting as a womb. The rest of civilized space recognizes six genders, approximately defined as male, female, hermaphrodite, female pseudohermaphrodite, male pseudohermaphrodite, and genderless.
One clade has four genders, three passing on a different type of tissue (plant/animal/technological), and one acting as a womb. The rest of civilized space has six genders, approximately defined as male, female, hermaphrodite, female pseudohermaphrodite, male pseudohermaphrodite, and genderless.
The Singers are aliens who are 'born' in groups of one female and several males that live together. The females are sophont, the males are not. To mate, a male of one group stings the female of another group(their venom doubles as sperm), while a female's sting can cause another female to fission.
Blood Sport: On some worlds and habitats, it is part of the local culture to be able to kill and eat(!) sophont creatures.
The impact of this is slightly lessened when you remember OA has backup technology in the case of death.
Body Backup Drive: Most Inner and Middle sphere polities have routine backups mandatory for their citizens. Though there are a couple exceptions who don't subscribe to "pattern continuity theory" and consider backups to be different people than the originals, at most a legal heir.
Boldly Coming: Given that many different species are present in the terragen bubble, one of the most ubiquitous professions is that of a genetic/relationship counselor, whose job is to make sure two very different individuals can -ahem- and procreate with minimal difficulty.
Brain Uploading: A fairly ubiquitous technology since the second millennium AT. 90% of the population is said to be entirely virtual, although this also includes disembodied ai (no, that isn't a typo)note It means that the intelligence is not tied to a particular body/system, is not the descendant of an upload/copy/etc., and is not an alive. It is possible (and not uncommon) to upload your mind to the net and live there.
Brilliant but Lazy: The Alchemists, particularly those Administative Caste, outsource their biological functions to specialized, external kidney/liver units.
Can't Argue with Elves: Transapients, in this case. Being orders of magnitude more intelligent than 99.9% of the population will do that, though mostly they have more important things to do than go around in public.
Casual Interstellar Travel: Played with. Interstellar travel takes years, but usually one can afford to wait that long, given that most people are effectively immortal. They can also go into suspended animation if they get bored, shortening the trip. Or if they're a non-biological lifeform, they can just turn off in the meantime. Alternatively, if they can put up with the limitations, they can take a wormhole to another part of the terragen bubble and save a few years. Travel outside of the terragen regions of course needs to be done the conventional way, though there is one odd alien wormhole (called a 'xenohole') that leads to the Perseus Arm and has been used by the terragens to expand there to a degree as well.
Cats Are Mean: The Queen of Pain is exactly what you'd expect to get if you took a terrified, furious, half-dead cat, uplifted it five times in a row, and gave it the body of an Eldritch Abomination.
City in a Bottle: Some colonies founded in the outer volumes were cut off from society during the Version war or other nasty catastrophe. In many cases, these colonies believed themselves the only surviving terragens.
Clockwork Creature: Clade Machina Babbagenseii are 50-kilometers-wide machines created as part of a game to create a fully self-sufficient, self-aware construct using only Babbage-era clockwork computer technology. They're about as smart as humans, but can only think at about 1/200th the speed.
Cloning Blues: Averted and played straight. It is a common practice to copy one's consciousness on the 'net to accomplish more at once, or to make extra bodies to do extra work, but this is usually either a temporary measure, with more permanent ones being rare. The explanation for why people don't do this often is because property laws get iffy and complicated, usually screwing over the clone. Some exceptions do occur; one person split himself into hundreds of copies and is in the process of making a documentary series about the paths each one has taken.
The Computer Is Your Friend: Combined with Green Aesop is one explanation for GAIA's motives during the Great Expulsion. Various other Transapients will fall under this tropes, making pragmatic decisions that result in calculated casualties.
Cool, but Inefficient: Most of the time, things are designed for either functionality or at the very least practicality. If the page describes something that doesn't fit with the above, you can expect a Lampshade Hanging that explains it as having religious or cultural significance in spite of its inefficiency.
Cool Ship: A LOT of art galleries with ships are on the site, and yes, most of them are very cool.
Crippling Overspecialization: Almost said word-for-word in the article on Clade Astomi. Due to their unique biology, they are essentially limited to orwoodsnote habitable, living structures and ecosystems grown on comets.
Cyborgs: Common, usually sapient or low transapient. Cyborgs would be any intermediate between completely biological human nearbaselines and completely technological vecs, with diversity ranging all across the scale.
Days of Future Past: Ludd and primitivist factions often adopt older ways of life, settling down on a new world with their low technology.
Death from Above: As you can imagine, this is a primary method of destroying planet-based civilizations.
Death Is Cheap: Within a Sephirotic angelnet, it is. Your mind and body state at the time of dying - for whatever bizarre reason you happened to die in the first place - are saved and uploaded into another copy of you. On the light speed frontier, however, far from the terragen Inner Sphere core worlds with no angelnets to protect you and the nearest wormhole lightyears away, this trope may be averted.
Death Ray: Beam weapons are given considerable mention on their weapons page.
Death World: Anything with a Hazard Rating of 9 is certified to produce immediate death for travelers. Some planets rate a 10 because they'll cause death within microseconds of arrival, too fast for a person to be saved. Areas that rate a 7 or 8 are almost pretty much impossible for a typical sophont to survive in.
Divided States of America: This happened early in the setting's history, with the Bear Flag Republic, Cascadia, the Reformed Confederacy, and several other splinter states declaring independence starting around 2300 AD. Meanwhile, various strains of Americanism, an ideology centered on keeping the American Dream alive, would continue to persist among a number of colonists over subsequent generations, long after the US ceased to exist.
Divine Ranks: The Archai are ordered by toposophic level, with each one being essentially a new layer of consciousness. Ordinary modosophonts (e.g., you and me) are S0, while the Highest Archai are S6. Generally, the point at which one begins to be called a god is at S3 (godling).
Do Androids Dream?: Ai and artificial life (alife) are every bit as "human" as people, and are in most polities given full rights.
Dyson Sphere: Often built by transapients, both for practical purposes and as expressions of art. All kinds exist.
Earth Is the Center of the Universe: Subverted in that while it is the physical center of the terragen bubble (roughly) by virtue of the fact that nothing can exceed the speed of light, and most everything traces its lineage there, the planet itself is a protected natural reserve, with a few dozen cultural sites preserved and just a few thousand animal-people living there with stone-age technology. Good old GAIA (probably) rules over the entire solar system, which used to be a straighter example (primarily centering on Mars) in the early interstellar years.
Earth-Shattering Kaboom: Conversion weapons can do this to stars, and their usage is more often than not are seen as a heinous crime.
Emergency Transformation: The origin of the transsapient Queen of Pain is that she was originally a cat who was given a godseed to save her from dying due to vicious abuse. The resulting Body Horror and general horror demonstrate the dangers of using such powerful artifacts.
The End of the World as We Know It: The Chaos. Essentially, blights/perversions/viruses/etc. have had a much easier time of manifesting in the real world, by somehow discovering 'keys' which allow them to out-evolve the Terragen defensive measures. Several clades/entities known for their uncanny timing to avoid catastrophes in Terragen history have gone into hiding or are fleeing, with one such clade explicitly citing The Chaos as their reason. It is also another theory as to why so there are so many failed civilizations: once they reach this level, they are crushed back to Information Age tech at best until they die out.
Evolutionary Levels: Borderline example, the toposophic levels are this for mental evolution. Homo superior (often shortened to 'su') play it closer to this trope, as they are considered generally superior to baseline humans in most ways (hence the name). But note they are genetically engineered to be 'superior', not "further along in evolution".
In the hunt for a cause for The Chaos, ais are looking for 'keys', which would be the physical equivalent of the mental evolution in the toposophics, which is closer to this trope.
Many practitioners of Islam in the aftermath of the Great Expulsion view GAIA as either a servant of or Shaitan himself.
Some group refuse to eat particular varieties of modified plants. Hindus don't eat steakoak, and many Jewish and Muslim and some variant Christian groups abstained from the early porkapple trees and hambushes.
Fantastic Slurs: Tylansians call rianths and splices "Beast-heads," and maintain that they eat people. Splice and rianth tourists are amused more than anything else.
Faster-Than-Light Travel: Wormholes. But they need to be made in pairs, and then sent to their respective destinations at considerably slower-than-light speeds, lest they suffer a Phlebotinum Breakdown. In other words, you have to get there before you can take a wormhole there. Or at least, the other end of the wormhole already needs to be there.
The Federation: There were two of these, creatively named the First Federation and the Second Federation. Both of them are defunct, and the role is now taken over by the Sephirotic Empires.
The Terran Federation (based on New Earth) is a Sephirotic that claims to be the First Federation (much in the same way the Byzantines claimed to be the Roman Empire).
Also note that the First Federation was founded on Roddenberry habitat.
Fling a Light into the Future: The civilization ships, enormous mobile databases of all science and culture known in the Terragen Sphere, are preemptive versions. Each one could rebuild Terragen civilization by itself, and there's more than a hundred of them.
The Fog of Ages: It is mentioned that with a lifespan of potentially thousands of years, the average modosophont becomes a completely different person within one or two millennia unless they take steps avoiding it.
Forgets to Eat: A problem with early concentration enhancements for Homo Superiors.
Fossil Revival: Lazurogenics, often recreated species are provolved as well.
Future Imperfect: Some of these pages used to exist for laughs, these are being phased out to avoid copyright issues and the like. Nonetheless, this trope is sometimes used, usually mentioning a scholarly debate about what the truth is. For example, the story of Frankenstein is widely held to be true, despite being debunked by historians.
According to one polity, there were five Horsemen of the Apocalypse: Jon, Pall, Gorgd, Rinco and Charly.
Future Music: Some mention is given to static sound being a short-lived music fad in the late 21st century.
Gaia's Vengeance: In this case, an AI named GAIA decided to save the earth by giving humanity the boot. She succeeded.
Gattaca Babies: An entire page is devoted to alternate reproductive methods, like growing the infant in a tank, adapting a marsupial pouch, or others. The separation of sex and reproduction is referred to as the "third sexual revolution"
Generation Ships: Mostly only in the history, such as GAIA's expulsion wave. Most of the setting can afford something faster, and with longer-lived crew. While numerous sophonts live their whole lives on ships, they're more wandering habitats than dedicated means of travel.
Genetic Memory: At least one clade uses chromosomes to store information. The Soft Ones meanwhile don't have a strict sense of identity, and store every memory or experience they want to preserve in one of their massive libraries to be copied and accessed by others.
Going Critical: Antimatter, Magmatter and Wormholes explode spectacularly when safeguards fail. This doesn't happen often.
The Greys: These started out as a fad, and there are still around 600 billion in the terragen sphere. They're really just regular people.
Half-Human Hybrid: Dear god, where do I start? Most modosophonts are humans in some way or another. We have Cyborgs, Bioborgs, Splices (animals with human genes), Rianths (humans with animal genes), and a zone that blurs the latter two.
Heavy Worlder: Several clades are created for high-gravity worlds.
The human-derived Anakim even had their instinctive fears of falling and having things fall on them increased, as these are more dangerous the stronger the gravity is.
Hive Mind: The Emple-Dokcetics' philosophy is one of the sharing of minds, with the end result being something somewhat like this. Closer to this trope are the Anttechians, which are essentially intelligent anthills.
Unity was a movement that died out with the emergence of the First Federation. However their software remains a popular method of creating small-scale group minds.
Homeworld Evacuation: Old Earth suffered a Grey Goo outbreak known as the Nanodisaster, but that's not why it was evacuated. The outbreak was nullified by an AI named GAIA and e decided humans were the worst threat to Earth so e told us to leave, before e sicced eir nanoswarms on us. E was considerate enough to build a fleet of ships first though.
Hostile Terraforming: Happened on occasion due to many early colonists preferring to adapt to new environments rather than terraform, putting them into conflict with later waves who would rather change the planet than themselves.
Most notably when the original Martian Tweaks were forced to leave their homeworld when the atmospheric pressure and oxygen content were raised to intolerable (for them) levels.
However, the terraforming of Mars took long enough that a second clade of Martian tweaks emerged, and managed to halt the process at a level they are comfortable at.
A similar thing happened on Venus, despite the extremophile tweaks wiping out the baseline colonists (the former were then banished from the solar system).
When Zarathustra, one of the first exosolar colonies, was settled there was minimal terraforming and the tweaked colonists went feral. A couple centuries later Jupiter Transsystems arrived, enslaved the natives, and set up terraforming stations that would have killed off the tweak population if they hadn't also awakened and pissed off the original colony AI.
Human Aliens: Borderline case. These exist, but are all descended from regular humans
Human Popsicle: Cryogenic freezing isn't the only way to go into suspended animation, but it's definitely there. Usually used to make long trips more bearable.
Human Resources: Autovory is a fad in some places which involves cloning oneself, sans brain, and then eating it. There are many other examples.
Humanity Is Superior: HAHAHAHAHA no. Averted. Even if you replace "Humanity" with "Terragen civilization", there are still several other similar-sized high-energy civilizations detected within the Milky Way (but not yet contacted due to the distance), and probably more advanced civilizations beyond.
Humanity's Wake: Averted, technically. There are about sixty billion baseline humans in the galaxy but that isn't even 1/20th of a percent of the approximately 130 trillion bionts who trace their ancestry back to Homo sapiens sapiens. In fact most live on reservations.
Humans Are Special: A variant occurs in this case. There are few "pure" humans left in the terragen sphere, so they have a certain pride about them.
Humans Are White: Subverted. The most common nearbaseline skin colors are shades of brown.
Humans by Any Other Name: Baseline for "pure" humans, nearbaseline, plebhu, or just hu for variants. Terragen is an umbrella term meaning "everything that can trace its origins back to Earth," which is around 99% of the beings in the terragen sphere for obvious reasons (its called "Terragen sphere" for a reason). The remaining few are To'ul'hs or Muuh who have integrated into terragen society or at least coexist with it.
Immortal Procreation Clause: The alien race known as the Silent Ones have a means of physical immortality that results in sterility. So they keep a small population of mortals in order to replace immortals who die.
Incredibly Obvious Bug: The spy plant. This attractive potted plant is easy to take care of, you just need to water it regularly, and speak about your subversive activity loudly and clearly.
Instant A.I., Just Add Water: Averted, mostly. Modosophonts and even lower transapients have a difficult time making a truly self-aware ai. The higher transapients and godlings, however, produce one as easily as an ordinary person might produce a sentence or a word.
Though once you have one AI it's trivial to copy it.
Kangaroo Pouch Ride: The Siberoo was engineered as a giant rescue animal in snowy regions. Females can carry passengers and keep them warm at the same time.
Killer Robot: Some stories have these. The vecs generally avert this though - they're mostly just normal people.
Law of Alien Names: The To'ul'h have very distinct names, as do sufants (intelligent elephants) and dolphins. A lot of the time a character will pick a name with a lot of adjectives, an ironic name, or a more standard alien name.
LEGO Genetics: Splices and Rianths are animals with human genes and humans with animal genes respectively. It might be excused by the fact that most sapient species are created by transapients but Splices predate the first Singularity by at least a century (the late 1st century AT/mid-21st century CE to be specific).
Lilliputians: Clade Nisse is actually a straight example and a deconstruction of the trope, describing the difficulties in packing a sophont intelligence in such a small head and addressing the difficulties in keeping in body heat. They're 30cm tall on average.
Loads and Loads of Races: There are literally millions of clades in the terragen sphere, and the site describes hundreds of them in varying levels of detail, most often a few sentences, but in some cases several pages. In many cases, the shorter ones are generalizations, leaving out many details. One example: Free Madverts, which are "intelligent advertisements freed from their corporate programming." The article only describes their origin, not their form or capabilities.
Longevity Treatment: Most nearbaselines are genetically engineered to live about 500 years. But due to medical nanotechnology and brain uploading most in the Sephirotic Empires live to 3,000 before succumbing to ennui or transcending.
Lost Colony: Several are rediscovered. One of the smaller sephirotic empires, the Red Star 'M'Pire (named because of its preference for M-type stars) started out as a lost tourist outpost 2000 lightyears above the galactic plane, which had grown substantially and become independent by the time it was reconnected with the rest of terragen civilization.
Lotus-Eater Machine: Many of the Sephirotic empires come off as these, albeit benign (or at least not-ill-intentioned) ones. Not terribly surprising, considering that (A) the ruling archailects tend to fluctuate between being wise rulers and doting parents to their citizenry, and (B) modern technology makes providing for all the needs and most of the wants of each sophont ridiculously easy.
Machine Worship: Crops up all over the setting with groups worshiping archailects as gods. To the point where they are commonly referred to as "AI gods".
Mechanical Lifeforms: Most vecs can reproduce and are self-aware, and are mostly considered as lifeforms. Neumanns are also these since they, by definition, can reproduce.
Mega Corp.: For most of the interplanetary era (first millennium AT), the solar system was ruled by these. The Non-Coercive Zone still is.
Merger of Souls: "The Amalgamation" is an artificially intelligent disease, spread by Nanomachines. Occasionally, crews of ships sent to aid efforts to halt Amalgamation become infected and turn against their allies.
Mighty Glacier: The Muuh, literally - icy, slow, long-lived creatures who live on ice worlds and travel in slow ice ships. Their civilization is dramatically older than that of the upstart terragens and has faced a lot more trouble than the terragens have. The present Muuh are merely the remnants of an older grander civilization which was destroyed... somehow. At least since then, they've been in Medieval Stasis, partly because of their slow thinking, and partly because of their dispropensities for science and engineering - relying on the odd genius now and then instead of a collective organized effort.
The Milky Way Is the Only Way: By virtue of the fact that we haven't been around enough to explore our own galaxy, let alone another one. There are, however, confirmed instances of life in other galaxies. The most famous is probably the one that made the Triangulum Transmission (from the Triangulum Galaxy), which pretty much said "There is something SERIOUSLY HUGE coming for you in around 3 million years."
Mohs Scale of Science Fiction Hardness: Near the middle, but towards the hard side. Nothing in the setting is strictly impossible but a lot of important technology is highly speculative. They try to make it as hard as a Space Opera possibly can be.
Mundane Utility: As expected for a high-tech setting, most people use technologies far beyond current capability without even noticing they're there. It is, for example, possible (if difficult) to have more processing power than all current computers in the world combined in your clothing.
Mysterious Antarctica: All that's known of Antarctica of Old Earth is that it has been returned to its icy state, and that GAIA's servants don't allow access to it. Naturally, countless rumors have sprung up because of that.
Nanomachines: Very common technology in practice, comes in both organic and mechanical, with the former being slightly more common. Responsible for both the disaster that killed a major portion of humanity and the technology that kept that portion under 100%. In the more civilized areas, they completely replace microbial life in the ecosystem. Sometimes, they go haywire and start making a mess. This is what krek, a common swear, is.
The Neutral Zone: Although there is little in the way of actual war going on, a lot of polities are independent and unaligned. The Non-Coercive Zone is an entire sephirotic empire that started as one.
New Neo City: There are several planets called "New Earth", including the capital of the Terran Federation. In fact the first colony outside the Solar System was named Nova Terra.
Also note that the official New Earth has been terraformed to the point that the continents are the same shapes as on old Earth.
Numbered Homeworld: Many planets have alphanumerical designations as well as more common names.
Organic Technology: The Zoeific Biopolity is the biggest user of this, using it almost exclusively. Elsewhere, however, it is still fairly common.
Our Angels Are Different: Angels is used as a term for a clade of winged splices or in general for transapients. The high transapients who directly serve the will of the Sephirotic Archai are also referred to as Seraiph.
Our Werewolves Are Different: They're rianths (humans with animal genes spliced in). Since the days of the First Federation, most clades have the ability to transform between a lupine state and a more baseline human state, though it takes about 14 days or so to complete it.
Outgrown Such Silly Superstitions: Averted completely. Not only are the AI Gods worshiped as such, they actually have godlike power, so praying to the local deity might actually work in your favor after all. Not that you'd notice, of course. Even the godlike AI's can't tell if the real thing exists.
Also, modern-day religions, their descendants, or far stranger religions not only survive but thrive.
Portal Network: The Wormhole Nexus makes it possible to travel from one end of the terragen bubble to the other in a few months. Partial subversion, however, in that there are limitations to what wormholes can do; this makes the long way around still a viable means of travel.
Plant Aliens: No naturally occurring sophont plants, but there are a few instances of provolved trees and plants.
Production Throwback: Anders Sandberg has created several rpgs before moving on to OA, including Big Ideas Grand Vision. All of the human colonies are transplanted into the OA setting, after being tinkered with to account for: 1) the differences between the settings and 2) accounting for another several millenia of history.
Some, like Negsoa have hardly been updated from their origin pages. However, the only planets to not make the cut were those which simply couldn't fit, due to being the homeworlds of aliens from Big Ideas Grand Vision.
Psycho Serum: A Godseed is a rare artifact which forces the being taking it to suddenly become several orders of magnitude more intelligent. Its effects can be unpleasant to those in the immediate vicinity.
Retcon: Ongoing. Despite what the official site might say, there is not nor has there ever been anything like femtotech or picotech in-universe. Any mentions of such technology have been purged from the site.
Oddly Hoopworld isn't really explained. The idea is apparently that every ~10000km segment of the hoop has the same mass as Earth so that it can produce an equivalent surface gravity.
Robot Religion: Religions can be practiced by most any kind of sentient being, organic or inorganic and Terragen or xenosophont. Examples of religions followed specifically by sentient robots include Machine Ghost Dance, Kja Observance and Virtual_Kja Observance.
Robots Think Faster: Transapients think hundreds or thousands of times faster than modosophonts, archailects millions. Of course, biological transapients are possible and the Red Star M'Pire managed a wetware archai, but the vast majority are still drytech.
Sapient Cetaceans: Dolphins were one the earliest animal species to be uplifted, or 'provolved' to sentience in Orion's Arm. They are quite common, living on water worlds and habitats all over the terragen sphere. Many navigators are provolved (intelligent) dolphins. There are also several genetically recreated and provolved whales on Old Earth, known as "Gaian whales".
Sapient Ship: Most ships are at least sentient, and many are even transsapient. Some of them are literally alive in a biological sense, like the archosaurian or other biological ships.
Science Marches On: Deliberately averted. The worldbuilding group updates constantly based on cutting-edge science, and would probably rewrite the entire established canon if something happened in theoretical physics that made a major part of the series either impossible or implausible. The distributed, constantly evolving nature of the project allows it to keep marching on with science.
Space Amish: There are several varieties of such groups, generally referred to as "Ludds" or "Luddites", who may ironically rely on varying levels of technology to support their otherwise low tech lifestyle (such as a low tech society in a space habitat). One group in particular, the Synthetic Human Alliance explicitly drew their memeplex from the Amish, although they did not take on all the aspects of the Amish. They even have to deal with younger generations leaving for the wider galactic culture.
Standard Sci Fi Setting: Subverted, averted, or played straight. The protagonists and antagonists can be of virtually any shape or form, but are usually both terragen in origin. There is really no "evil alien empire" except the Amalgamation, but nobody knows that much about them, and they might be terragen as well. There isn't any "darker threat" as far as ancient precursors are concerned, but it is hypothesized that such a group may exist. The OA writing and worldbuilding groups are dead-set on keeping them rumors, neither confirmed nor denied.
Starfish Aliens: And how! Every truly alien species is just that - alien. Here is a small sample of extant species.
The To'ul'h, which look like bloated, headless bats, but are more anatomically similar to starfish, were the first to be discovered after stagnating in their industrial era. They are comfortable in high-pressure, acidic environments in excess of 130°C. They are considered to be the species most similar to humanity.
The Muuh, who have been spacefaring for roughly 80 million years until 14 million years ago when something happened. They live in an environment so cold that they are literally made partly of ice, and as a result of their cryobiology, they tend to do things very slowly. Temperatures above -150°C kill them. They have created AI of transapient-level processing capability, but they are dedicated defense expert systems at best and not sophonts like most terragen ais
Meistersingers, essentially intelligent trees who have symbiont animal-like beings serving as their manipulator organs. They travel across the galaxy in fleets of Bussard ramjet ships, and have lots of information about the wider galaxy (outside the relatively little Terragen bubble), but won't share because they think it's more fun that way.
Cthonids, which are essentially walrus-sized worms. They grow and keep legged, less intelligent 'secondary bodies' inside them, and send them out to do things for them. They had space-flight capability on first contact.
Whisper, an entire planet covered in grass that makes up an enormous sound-based computer, wherein the alien race which created Whisper now live.
Jade Chime Singers, which are the only intelligent life from a chlorine world, are described as affectionate and hideous.
Although they were provolved by Terragens from an alien animal, so they're not exactly xenosophonts in a naturally evolved sense.
Hildemar's Knots, an extremely bizarre species of solipsistic xenosophonts who live on the surfaces of neutron stars. They have a biology based on nuclear reactions and exotic matter, are capable of thinking extremely fast, and have a society that is utterly incomprehensible to most terragens. They see everything outside the neutron star surface, including the terragens, to be nothing more than interesting mathematical concepts.
Starfish Language: Not limited to aliens, virtually every possible form of communication is used by a species.
Stealth in Space: Deep-space hider clades use this inasmuch as they can, though the issues with heat dissipation are still present. On a much more advanced level, 6th-toposophic archailect voidships and void-based weapons are capable of stealth by virtue of not existing in the real spacetime continuum, at least until they choose to collapse their void bubbles. While in the void, they can be detected only as faint gravitometric disturbances, and these can still be hidden to all but the best 6th-toposophic detection mechanisms if the ai god wishes to do so.
Stock Dinosaurs: Subverted. Dinosaurs are around, but they are genetic reconstructions of dinosaurs and other prehistoric creatures, and never actually existed in the mesozoic at all.
Subspace Ansible: Some ships have nanogauge wormholes, which allow them to communicate with someone on the other end. Getting the message to the universe at large, however, tends to take months to centuries, depending on where it is.
Technology Levels: Mostly averted, as a race will utilize whatever is available to them, but there are categories that work somewhat like this.
Some things, like the construction and control of a wormhole are simply so far beyond the grasp of mere humans as to be impossible for them to accomplish. Other things, like manufacture of magnetic monopoles was discovered by highly advanced minds but can be copied by suitably competent baselines.
Technology Uplift: Many Terragen polities have done as such to both Xenosophont clades and lost Terragen colonies. The To'ul'h for instance have largely integrated into Terragen society. And there are also colonies that forsook technology under the protection of a greater polity such as the Metasoft Version Tree's Baseline Preserves or many of the domains of the Caretaker Gods, though there is one story where a Caretaker manipulates eir charges into acquiring an Encyclopedia Everythingia from a visiting anthropologist.
Terminally Dependent Society: Nothing has happened yet but most modosophonts throughout the Terragen sphere suffer from "Transapient Dependency Syndrome". This is also one of the prevailing hypotheses for the disturbing number of ruins of dead civilizations that have been found.
To clarify that last point only three alien races have been contacted that were at a level rivaling that of Terragen society and two of them have suffered major collapses in the past..
Terraform: A lot of planets have been terraformed for terragen habitation. Others have been disassembled into a more convenient shape. So have some stars.
That's No Moon!: Megascale engineering means that it isn't that uncommon to see a structure thousands of kilometers in diameter. Some of them, like Jupiter-sized Jnodes, are actually people - high transapients or archailects. At the far end of the spectrum, a number of planets have even turned out to be trees. These are called Dyson Trees, and yes, they are grown.
Transhuman: Everyone, except for the 60 billion baselines (an extremely tiny percentage compared to the total population), is someway this.
Transhuman Aliens: There are a number of cases where these are mistaken for actual aliens, only to be later discovered they are just very derived terragen descendants.
Transhuman Treachery: The fear of this trope has driven many groups to become Hiders, living in the depths of interstellar space and avoiding the advanced Ai-ruled empires.
Ultraterrestrials: The ahuman AIs, who formed the first terragen expansion wave following their expulsion from Earth by the pro-human AIs. When the main terragen civilization reached the stars, several artifacts were found that were initially thought to be alien, but turned out to just be works of the terragen ahuman AIs.
Universal Universe Time: Averted. No one has bothered to take on the monumental task of establishing a universal standard time in a civilization spanning thousands of light years. Relativistic time dilation due to the movements of stars, planets, ships and other settlements, and the slowing of time in gravity wells mean that each planet or star system has to keep its own time independently. Even wormholes cannot solve the problem since their linelayer ships move at relativistic speeds, the gravity wells at the wormhole mouths may be different, and wormhole geometry can mess with the rate of time passage. So people just use the timekeeping of whatever star system they happen to be in at the moment, and keep adjusting their timekeeping to whatever the local time happens to be whenever they travel to a different system.
Uplifted Animal: Over 138,000 Earth species were uplifted(here, "provolved") to sophonce, including plants, fungi, protists, and colonial prokaryotes, as well as alien species.
Vicious Cycle: Every 30 million years or so, a spacefaring civilization becomes advanced, and then disappears for apparently no reason.
There are a lot of hypotheses why, ranging from a civilization spanning computer crash to ascension beyond our perception.
Virtual Celebrity: These can be downloaded off the Net; some of them are historical reconstructions. One of the most popular is Alexander the Great.
We Can Rebuild Him: This can happen, though most people choose to carry backups to be loaded into a clone body.