In the near future my group will be going up against a star cult, which prompted me to create some new monsters in accordance with my level and thematic requirements. If they're reading this, they can go ahead and take a peak, or stop and be surprised.
Neophytes are cult newbies that haven't been "rewarded" with any appreciable mutations. They're better when they can get flanking, but in general aren't that much trouble.
Acolytes are neophytes turned up to 11. They are more dangerous when flanking, but due to whispered portents and multiple eyes cannot be flanked. Also, they can teleport, which is great for maneuvering but also to gain combat advantage against an enemy.
Warlocks are, well, warlocks. They can tear open the planar fabric to conjure up clusters of grasping tentacles, or emblazon their foes with baleful signs. Mostly they just stick to eldritch blast while applying their curse.
Husks are the cult's guardians. Most people that are exposed to the baleful energy of stars die. They're the lucky ones. These guys didn't die, and now simply exist as roughly humanoid cinders that obey their masters. Husks draw their enemies close with their gravity well so that they can crush them with fiery slams, and can even fold space in order to better protect their charges.
Voices claim to speak for the stars, when they say anything coherent at all. They spend most of their time frantically scrawling the messages that the numerous mouths on their bodies whisper to them, which they can levy on their foes in order to instill insanity and terror.