In Worm the Endbringers are getting closer to destroying the world, having destroyed entire cities and killing millions of people. Due to how super-power trigger events work, villains greatly outnumber the heroes, with a few being exceptionally horrifying and powerful, such as the mass murdering SlaughterhouseNine (amoral psychopaths with superpowers team up!), who are so dangerous that driving them off is the closest you can get to victory. Many of the “heroes” of the world, are anything but, and the protagonists are supervillains.
When a reader of Legion of Nothing raised the possibility of a crossover with Worm, responses included, "some universes are too dangerous to explore", "that would be bad" and "based on what happens to many of the characters that actually inhabit the Wormverse..."
Tech Infantry is partly based on the Old World of Darkness, so of course it's a dark and pessimistic world, with an oppressive and corrupt government, genocidal aliens, ancient supernatural entities manipulating the unawakened human population for their own mysterious ends, and any idealistic characters quickly getting the hope kicked out of them by a callous and indifferent universe.
In Vatsy and Bruno, the streets are strewn with garbage, the skies are grey, the protagonists are a pair of non-tax-paying vagrants whose only talents involve criminal acts and the organizations oscillate between ludicrously incompetent and outright murderous. It's a comedy.
Tankmen starts with the war-torn remnants of a city, but what what makes it so crappy is that the warring factions don't even know what they're fighting for, but keep on warring as if it were an average 9-to-5 grind.
In the Colour My Series, there's a long list of forbidden activities on the stick-figure citizens. Among these are pets, plants, running, emotion, color, and smiling. There are huge robots to enforce the laws, too.
You can see a pretty good example of this on the SCP Foundation, a pseudo-governmental organization built around containing, securing, and protecting humanity from strange creatures, objects — and people. This is all the more obvious in the roleplaying scenarios, where Agents, Doctors, and Beings are entitled to eliminate anything from the face of the Earth if it poses a significant, uncontainable threat. Or if it's a Mary Sue. Oh... and humans don't matter all that much more, personally speaking. Oh and it's strongly implied in the various articles that a) humanity was created by mistake and b) the world is going to end soon and there probably isn't a thing the Foundation can do to stop it.
In Underground Crushed Underground by sam512, what seems to be all of humanity is imprisoned in a giant underground arcology, doomed to toil until they die. The word "dystopia" is explicitly used. That's bad. It gets worse. They're trapped in the arcology because it's actually a giant fallout shelter, holding the only survivors of humanity. With the outside a radioactive hellscape, and the biosphere completely destroyed, it'll be another two thousand years before they can leave the arcology. The immortal Governor only kept it from the proles to keep the suicide rate down.
In the universe of Addergoole and Wild One's Blood, the Ellehemaei are royally screwed by the Universe, since even casual promises are mystically enforced by "The Law." Oh, and if you manage to break free and defy The Law you apparently turn (more) evil. The Addergoole of the title is a Boarding School of Horrors where teenaged Ellehemaei, who at this point think they're human, are thrown in the deep end of their screwed up society.
In We Are Our Avatars, the World the Consolebots come from counts as this. Even after the Great Liberation, it's still pretty bad.
From a world of Superheroes comes Dusk City, a city full of pollution, corruption, and a few other things, including superpowered criminals and an arms-smuggling ring. The Past District in the town, which bases itself in the 30s and 40s, actually seems more pleasant.
Foxforce. In this world there was no space race, no NATO, no UN, no Star Trek, no Live Aid, no Israel, no global vaccination programmes, no VE day, no 13th Amendment, and no Emancipation Proclamation. Science still marched on, but in new directions. Artificial intelligence and artificial life are both very real, and very sentient, and can be brought and sold online. Imagine, if you will, a world where organisations like PETA campaign not for the rights of animals, but the rights of slaves, and yet are held to the same level of contempt. This is the world of Firefox, Technofox, Silverfox, and (coming soon) Shadowfox.
The world inhabited by the title characters of Lego Pirate Misadventures is pretty grim for a Lego world. Pirates apparently own at least one city, have an academy dedicated to learning the trade of raping and pillaging, and are ruled by a guild stuffed full of Obstructive Bureaucrats. This city also has a hit TV show called "Torture Time With Mr. Cuddles" where people get tortured to death, and people get gunned down in the street for little to no reason. No one seems terribly bothered by any of this, though.
The AlternateHistory.com timeline, For All Time, beginning with the death of Franklin D. Roosevelt shortly after Pearl Harbor, basically takes Finagle's Law and applies it to 20th-century history. In this world, all leaders are either corrupt, incompetent or insane, nations get splintered or thrown into civil war on a daily basis, and nuclear weapons get tossed around like snowballs.
China is the worst hit, with the Lesser Mao turning the country into a giant Pol Pot style killing field in the worst mass murder in history, including launching nuclear attacks on his own people. Since then it has crumbled into utter anarchy with no sign of recovery.
South Africa under Apartheid is a fully fledged Neo Nazi state in all but name, and wields an arsenal of WM Ds including dirty bombs which it hurls at it's neighbours with wild abandon and is fully protected by President Rumsfeld as a "bastion of freedom" due to the increasing insanity of his anti-communist paranoia.
Britain is even worse hit by The Troubles with many more deaths, including the assassination of Queen Elizabeth, and while it momentarily dies down it flares up even worse in the 80s due to a new "Loyalist" terrorist group launching attacks on the British mainland to punish any attempt to end the bloodshed and again this is directly aided by Rumsfeld in order to "punish" Britain for voting in a Labour Government.
America is getting dragged further and further towards fully fledged authoritarian police state under Rumsfeld, complete with the murder and internment of any and all critics, mass production of propaganda movies to smear the president's enemies, and all kinds of far right and christian fundamentalist fanatics employed and positions adopted by the administration. All while it's economy steadily falls apart. Rumsfeld and Cheney even privately admit they plan to remove each constitutional right save the right to bear arms (in order to keep the right wing happy).
Ironically the only country which seems to be improving is the Soviet Union which is steadily adopting Real-world China style reforms and is drawing Western Europe into it's orbit with ease given the increasingly psychotic and vindictive Rumsfeld. While it is still an authoritarian regime, it does seem to have a good chance of emerging from the 80s as a freer and more prosperous country than America does.
The future world from the ARG based around Nine Inch Nails' "Year Zero" album is a world where the US has become a repressive and insular theocracy following multiple chemical and biological attacks against it. US citizens are kept in-line via drugs in the public water supply and easily-available and highly addictive street drugs like "Opal" which come from government-funded pharmaceutical corporations. Global warming has made the equatorial regions of the planet nearly uninhabitable (and indeed has affected the climate enough that there is baseball being played outside in St. Louis in February). The rest of the world seems to be in a constant state of brush wars where American soldiers are kept on the knife's edge of psychosis with military drugs. The world is so crapsack that even visions of a god-like hand reaching down from the sky that cause electronics to fail and observers to go insane, might really be only a side-effect of easily-available government drugs, or just global hallucination brought on by the hopelessness of the real world.
Some of the stories has the futures to be in this, however, since it is not certain on what Madgie did to cause it, so yeah, what DID Madgie do?
While the main story of Ghost K is a fairly standard science fiction, the spinoff series K21 Squared has oppressive corporations running nations in the name of profit at the expense of human rights, anti-capitalist rebels as bad or worse than their enemies, technology capable of rendering someone a slave, and the eponymous Ghost_K wields next to no power to prevent this happening.
The Fear Mythos. When the friggin' Slender Man is just one of an entire pantheon of Eldritch Abominations all out to make everybody's lives hell, you know you're fucked. When said abominations are all based off of human phobias, and are effectively invincible, it's time to kill yourself. Only dying just hands your soul over to the Archangel. Not even death can save you. Oh well, if we're lucky The Quiet will unravel the universe before the other Fears make any large scale moves.
OH GOD THE RAPTURE IS BURNING shows what would happen if they did make any large scale moves. It's notpretty.
Several in The Wanderers Library, but Ur probably takes the cake. Lower class citizens are treated as nothing more than batteries for powering magic in Alteres, Harrhem is being destroyed by the very earth, and Etten is being slowly covered by an Eldritch Location created by gods afraid of death.
Rasa takes place on an original world named Albumere, which is ruled by objects called tabula. Every living thing is tied to a tabula, and the tabula can be used to completely take over what's linked to it. Furthermore, tabula rip those people away from their parents by at least four years old, leading to a world with no trust and no family where children, forced to grow up alone in the wild, are regularly killed and killers.
Kagerou Project: The story is set in a modern Japanese city, and seems like quite a nice place to live, but going on each characters' experiences alone, it becomes this: fathers burning their homes down (with two daughters inside), Mad Scientist killing two students; no one seems to care, mother abusing her only son, terrorists taking whole shopping complexes hostage; demanding 1 billion Yen, teen suicides, iron pipes falling from the sky - killing children, and have we mentioned child abuse yet? And this is all without mentioning time-loops and Medusae.
Rotten.com: The site shows the world as a frightening and, well, rotten place. Several articles in the Rotten Library talk about cruel rulers and conquerors, corrupt politicians and religious leaders, execution methods, torture devices, massacres, natural disasters, diseases, weapons, racist ideologies, yet they also have fun with it, by keeping an ironic style. Apart from the worst atrocities in mankind's history the Rotten Library also offers articles about more amusing and less nihilistic topics.