>>95997524
>Overlord
Being the master of a place full of super-human entities who are also quite hot is pretty much a top power-fantasy.
>RWBY
Magic academia with trashy waifus. Like, while it's not a harem anime, the setting is just the kind that you would expect for one. Not surprising that most fanfics are either gay or harem take on it.
>Supernatural
You either hate the setting and want to burn it or you read/wrote a lot of gay fanfics back in the day.