Hey,
As title says. Is there a black cloak ingame that are plain? No marks no other colors? Pretty much like the Tuxedo pants: https://www.wowhead.com/item=151804/black-tuxedo-pants#sold-by
My mog brain is going insane! 
Hey Elythel! There doesn’t seem to be any, at this time - usually cloaks have either a pattern or some other kind of color combination.
This page should be of some help, though! A few of the designs are fairly dark and plain 
Clever! A few pairings of hair styles and colors seem to cover the bright spot of the cape almost entirely, indeed 
