Anatomical Elements for Male Monsters

Roboman28

There are loads of monsters and alien products based on the Michaels but without genitalia. Now being alien they dont need these and you can imagine a different evolution but I think a monster with genitalia would be much more scary!

Serene Night

There are some. Raw arts monsters for gen 3 often have gens if it works with the shape. Personally I think monster gens shouldn't just resemble big human gens but I guess there are limitations 

pwiecek

Idelacio has a tumblr site, that I can't link to due to content (Don't go there if you're easily offended), that has (free) genitalia for several creatures.

Hooror foom the Deep

Maw Wurm

Grabber

Parasite X

Mean Green Mutha

There is also Anthromeat over at Renderotica