Of course it is possible. Logically, no one can prove that there are no different kinds. Perhaps you are referring to the articles that are spread everywhere on the internet about these different kinds.
But I ask, why the disguise if there is no deception?
Modern "researchers/authors" only mention three "kinds", but they never care about the the numerous age old cliches:
7. The little girl who lost her father
8. The seductress
9. The teacher/guide
11. The black dog
12. The python
That is why I mentioned "distraction" and it is working so well. All these researchers jumping in to cash in on this "new" paranormal phenomenon, they never care to refer to the ancient sources of eschatolology that have already discussed everything in detail, at least to compare with their research. I can assure you one thing DM, you can test this yourself with shadows (no matter what you believe them to be, whether guardians, devils, guides, or just activated archetypes but they) are not interested in individuals as persons. What would the "old hag" achieve by strangling a sleeping victim, a common person? How many same old hags are there in the world? Were they just replicated this way to appear throughout the world? What would the hatman achieve by just standing outside your window staring at you, and doing nothing?
If there are any different kinds, as far as I know, there are only two. The devils and the shadow-self. The rest are non-sentients like spiders, snakes and scorpions, cats and dogs. But even then all of them originate from the same lower plane of the astral.