Knowing what we know now about nano-travel and avatars, many of these beings are most certainly depicted in the shapes and forms in which they sometimes mocked themselves up in front of humans, either to intimidate or to show certain traits to create a specific impact on our ancestors.

We can sometimes get a hint of how they looked like in the Sumerian tablets as well, although the bodies they used here on Earth (and still do) are not really their original bodies, but were genetically manipulated and cloned to blend in better with the human societies of the time. 

Like author and researcher R.A. Boulay said in his excellent book, Flying Serpents and Dragons from 1990, in Sumerian times they seem to have showed themselves off as more majestic and larger in size than humans, just to emphasize their superiority, perhaps, and they kept their locked hair and long, braided beards. 

We can also see that their eyes are depicted as bigger than those of humans, with an odd shape, which is probably more similar to how their original eyes look like. 

We also see them depicted at times as extremely tall Reptilians, Dragons (even flying Dragons), people with bird-heads and human bodies, crocodile-heads, hyena heads, wolf heads, and jackal heads etc.; all with humanoid torsos. 

Knowing what we know now about nano-travel and avatars, many of these beings are most certainly depicted in the shapes and forms in which they sometimes mocked themselves up in front of humans, either to intimidate or to show certain traits to create a specific impact on our ancestors. 

Today, however, the bodies these people use when mingling with us are very human-like. 

In fact, they are neither giants, nor dwarfs, but are such that we could pass them on the street and never notice, except if we look them deep in the eyes. If we do, we may get this strange feeling that the person's eyes have more of a cat- or reptilian-like slit which bleeds through at times, while other times they are able to hide it.