Here are 8 additional factions/tradesmen/oddballs that may be found on and within Xor. Factions are not cults in any traditional or religious sense but they may still exercise customs as fervently as zealots adhere to their faith.
Tumor Grooms: This faction seeks out, nurses, and protects tumors of Xor until they are deemed ready to harvest. The odd tumors of Xor are rumored to have unique properties and flavors which most attribute to the reasoning behind the practice of the Tumor Grooms.
Scabrous Sculptors: these artsists cut into the flesh of Xor to release blood and other vital fluids which are directed and shaped as they harden over the inflicted wounds into a variety of esoteric sculptures.
Lice Whisperers: small bands of Lice Whisperers roam about claiming to be able to charm the lesser vermin of Xor and use them as scouts and minions. Lice Whisperer bands will work spells and sell talismans to ward against lice infestation and attacks; curiously enough those that purchase such spellworks are seldom attacked by lice soon afterward.
Skin Crawlers: these folk believe it is uncouth to walk about in one's own skin and fashion garb from the skin of Xor and the host of other creatures that dwell within and upon. The more grotesque a mask, the higher a peaked hood, the grander a cape, and the longer a scarf are all goals and signs of status among Skin /Crawlers. They find cloth contemptible and nonsensical in the presence of so much skin.
Womb Wardens: this faction of tradesmen has learned how to transplant a living fetus and see it brought to full term within a specially formed pocket-womb within the flesh of Xor. They guard the wombs from predators and charge a fair price for the overall service.
Mawpicks: scavengers that survive by picking the remains caught in the teeth of the many maws of Xor. Some carry the practice so far they will only dine upon beings they have captured and hurled into a maw.
Tickherds: the plentiful vermin that infest the skin of Xor are a resource that some depend upon and a variety classified as ticks have come to be herded as med off-Xor herd goats or sheep. The Tickherds dine upon the flesh of the ticks, "milk" the blood harvested by them, and fashion much of their gear from tick carapace.
Sweatmongers: these peddlers know how to collect, store, and mix the vast array of Xor fluids. They can seem as simple as water bearers or as erudite and schooled as alchemists depending upon their their personal range of lore and talents. Some groups of Sweatmongers maintain breweries that draw customers from far afield.
Yup I was infected with creativity upon reading the original Xor post. A pocket-campaign setting like Xor can fit in to liven up any boring spot of a more familiar campaign setting like the Dale Lands, Darokin, or pretty much anywhere on Krynn in addition to fitting in very well with Carcosa or somewhere outside Denethix. A Gamma World/Mutant Future campaign within and upon Xor would also feel fairly different from the more familar ruin strwen wastelands.