I have an idea for a new setting.
America is old enough and varied enough to be a campaign setting on its own. The plots and the locations already exist, and many of them are flat-out awesome. America already has civic undergrounds and witch crypts and Mammoth Cave and Sing Sing prison and Edison vs Tesla and presidents with shotguns.
Everyone else has a pet campaign setting; I want one, too. It will be eldritch Americana. Not modern fantasy or noir with wizards or dieselpunk or whatever. It will be a roiling celebration of all that is American, with all the feverish exuberance of the 1920s, already 30 years after the apocalypse. Gangsters and shoggoths. Speakeasies and hagfish-men.
I better write this stuff down before I forget it:
Late 1920s, immediately before the Great Depression. Women have enjoyed voting rights for less than a decade. Zeppelins, Prohibition, Swing Dancing. An age of optimism and energy. Hitler is coming to power. Stalin, too.
The apocalypse already happened. Most American cities are burnt shells inhabited by mad, thrashing things. The entire interior of the United States is horror-infested wasteland, effulgent with otherworldly energy and peopled with monsters. The cities that have survived have done so by walling themselves off and subsisting on fish and gin.
The interior of the country is a hexcrawl. The cities, prisons, sewers, shopping malls, and armories are the dungeons.
The dead have risen to eat the flesh of the living. Some converse and trade. Others hunt humans for sport. Others work for the Fish and Game Commission. Yet others run the subways, which remain the easiest way to cross the country. California is Ghoul-territory. All funerals are hasty cremations, for obvious reasons.
Flappers are changing society's views of women. Skirt hems are almost as high as the knee now, and leggings are--shockingly--available in nude tones. Ads are targeting women for the first time. Dating is in the process of replacing courtship, and Lysol is a leading method of birth control.
Opponent Earth, the planet that has always been hidden behind the sun, has decided to destroy us. They shoot giant "bullets" at us full of monsters. They also make it rain acid, poison, blood, monstrous worms, etc.
America is becoming acquainted with heroes and celebrities. Radio is just catching on. Franklin Delano Roosevelt is about to become president, and takes great pains to disguise his inability to walk (as a result of polio). Zippers are a thing.
The moon has "hatched", and new gods have claimed Earth as their own. Attenuated Satanists eat the black flesh from the titanic corpse in the Mojave, supposedly the Devil's own. It's been there for decades. . . it's too poisonous to rot.
Edison and Tesla are still around, ancient enemies after the voltage wars that nearly destroyed them both. After the electrocuted elephants and electric chair demonstrations, one of them is a rich and powerful business magnate, the other is a delirious pauper who talks to pigeons. Both are powerful electromancers.
Shantaks heave their corpse-bulk through the air above Chicago, shoving the air with heavy wings. Government hunter-killers hunt Mafioso bootleggers through acid-blackened streets. The faster car is the one that has incorporated more bizarre, semi-organic components, purchased from transdimensional traders. Gasoline is rarely produced, but the blood of Skethriman-Scolex, one of humanities new gods, works great in combustion engines.
The president is Silent Cal, a man renowned for his brevity. Formerly the vice-president, he advanced to his position after the early death of President Harding. Congressmen drink gin during the same meetings where they discuss how to enforce the massively underfunded Prohibition movement. The governor of New York is Al Smith, who was installed by Tammany Hall. The mayor of NYC is Jimmy Walker, who will soon resign amid a corruption scandal.
Rats vie with miniature shoggoths, which frequently merge during starvation. Electricity provided by continent-spanning network of naked mole-rat men, 4' tall.
The USS Los Angeles, a 656-foot zeppelin built by Germany as part of war reparations, carries passengers over the electric spires of New York.
The continent is devoured from the north by a transdimensional ice age. Mexico is a country of eternal night, where witch-god pyres send living smoke into the retreating heavens. No one has crossed the Pacific Ocean in years, due to the beasts that inhabit the new, nameless continent found there.
The KKK is in their heyday. They have embraced pointy hoods, burning crosses, and domestic terrorism in order to spread hatred and fear across the American Southeast.
Mages pay worship to the world's new masters, the unquiet, inscrutable Elder Godbeasts that are visible to anyone with view of the moon. The same mages channel alien magics, which invariably result in insanity, mutation, and death. Sometimes even in that order.
Marie Curie unlocks the mysteries of radiation, Stravinsky and Dali create masterpieces inspired by their private muses, and the Algonquin Round Table still meets for lunch. Fitzgerald and Hemingway get drink fantastic amounts of absinthe in Paris, where the larger author protects the smaller one from the predatory orifices of nameless things with a few steady punches.
Creatures called "dragons" ravage the countryside. Unique and powerful creatures empowered by vast and unknowable agencies from beyond our dimension. These are anomalous creatures, grown fat by stealing energy from the electrical vaults of the mole people. These are humans who have bargained with powers beyond space and time in exchange for awesome powers. These are the fungal behemoths who trawl the countryside, controlled by the hive-mind of zombie-wasps infesting their bodies. Each and every one of them is painfully and irrevocably insane.
By the end of 1929, the country will have plunged into a recession. The country will stumble, the world will worsen. Following the events of WW2, the otherworldly powers that gnaw hungrily at the Earth with sink their teeth in deeper, and by 1950 the last human will die in captivity.
These things are known, and they cannot be refuted.
But for now the few remaining cities of the United States burn brightly. The country is a fever-engine, turning faster and faster even as the tumblers melt and the flywheels shatter. In subterranean speakeasies, women wearing peacock feathers clink glasses with men in three-piece suits; together they string up toasts up like garlands. Everyone is careful not to ask where an absent friend is, lest the answer upset them.
The jazz band strikes up again, and although everyone is tired, they return to the floor anyway. There's still time for one more dance before last call.