what fetishes are in and what fetishes are planned?
Possession, Corruption, and Transformation fetishes are the main ones. So stuff along the lines of Ghost Possession, Slime Possession, Lesbian Domination, Skinsuit, Mind Control, etc. are in the game.
As for the planned fetishes that's a bit of a spoiler, but each of the dungeons I have planned focus on a unique kink/fetish.