I like to look for real people/organizations/ideologies for inspiration. For example, I recently looked through a bunch of fascist esoterica as inspiration for making a Shub-Niggurath cult that patrols the US-Mexico border looking for migrants to kidnap and eat/sacrifice. Might is Right is pretty much a Shub-Niggurath cultist's bible.

I'm also basing the lead cultist of off Measurehead from Disco Elysium. His cranial measurements (which he tattooed on his head) are gradually changing as a result of mutagenic exposure to the Dark Mother and he's sinking even further into psychotic alt-right delusions to cope with it.