how many types of extraterrestrial higher being we now known of? eg. the greys?

We KNOW of none.
There are no aliens, just peole with over active imaginations.

In actuality, none; zero, nada, zip, There is not one single bit of credible evidence we've been visited by any Aliens whatsoever.

The Greys
Predators
Alien(the kind in Independence Day)
Blobs

2 types...

Pleiadians, Greys

Example of a Grey would be the Roswell aliens. Those short, bald, big eyed things. A Pleiadian looks like a Human and some claim to be in contact with a few.

I know of ZERO.