I bought Carcosa a while back. There was a lot I liked about it, but a lot that was either too tedious or too icky for me to put into my game directly. So I started sticking in Jonathan Strange & Mr. Norrell. Like, rituals are more “convince this deranged fairy to help you instead of turning you into an antimacassar” rather than “throw an orphanage into a volcano and summon yet another scabrous mass of tentacles.”

So.

PERNICIOUS ALBION = CARCOSA + JANE AUSTEN + ENGLISH FAIRY TALES
Pernicious Albion is England where the pagans never died out, the Romans never left, and the aristocracy keeps their sterling silver sacrificial knives in the cupboard next to the fine china. 
The capital city is New Londinium, a city of black stone and alien geometries. It is filled with opera houses, opium dens, and shrines to the Outer Gods. Its ruler was once called Queen Victoria, but now she is the Midnight Mother, and worshiped as a goddess of forbidden knowledge and bodily transformations—the factors that led her to gruesome apotheosis. 
New Londinium’s power is unchallenged, but the many mouths of the Queen often whisper contradictory instructions into the ears of her courtiers, and so the wilds are as lawless as they are radioactive. There are four fairy-warlock warlords marauding through the wastelands of Carcosa, each powerful, each unstable, and each hating the other three with psychotic passion. They are The Regent of Midnight and Noon, who directs his clockwork horde from his clocktower at the End of the World; Pretty Tyrant, a deposed goblin prince with a taste for human flesh and an army at his back; Gogma, the last and most splendid of the Sea Giants; and the Red King of Roses, who lives in the carved shell of a gargantuan crab.
Classes:
Fighters are like this

Magic-users be like this.
Clerics are like this.

Specialist!

Druid
There are also Knights, which are reskinned dwarves, Paladins, which are reskinned elves with Cleric spells, and Rangers, which are reskinned halflings without the weapon restrictions. 
Inspiration: Jonathan Strange & Mr. Norrell, Pride and Prejudice, Comentarii de Bello Gallico, “The Call of Cthulhu”, Skyrim: Dragonborn