I had a dream last night that involved, among other things, seeing a group of small birdlike beings with fangs. They were about the size of ducks, covered in soft fuzzy white-grey downy feathers all over and where their beaks would have been instead they had muzzles full of a multitude of sharp fangs.
I have no idea what exactly they were although I feel that they were Otherworldly. They were also clearly dangerous.
Why am I sharing this story? I often have people come to me with encounters they've had with various beings, looking for names for what they've encountered. It's understandable. It's human nature to want names for things and to seek understand what we've experienced by relating it to a body of existing knowledge. When we first see a new animal we might have the same urge to find a name for it and seek out basic information about it. The problem we can run into though with beings not from our world is that even with the amazing store of folklore we have sometimes we encounter things that have no names and no known stories.
When people run into these unnamed or unknown* spirits and realize that they are unknown there is often a tendency to react by doubting themselves. As if just because the spirit they encountered can't be easily named and categorized the person themselves can no longer trust what they experienced. I think we need to be careful not to fall into that mindset that the only spirits and Otherworldly beings who exist are the ones who have already been recorded and defined by previous human generations; remember that even in the mortal world humans still sometimes discover new species. In the same way when we encounter the Otherworld and its inhabitants we should keep in mind that not everything there is known and defined by human understanding - indeed I would argue that its hubris to think that humans have such a complete understanding of the Otherworld as all that.
We also need to keep in mind that when it comes to the Other we aren't just talking about a single 'place' as it were or type of being. For myself I can speak with some confidence about whether something was likely a human ghost, and about a variety of types of fairies, especially from Irish, Scottish, and some Germanic cultures. But there are many, many other types of Otherworldly beings besides those, and beyond that there are many types of beings that are Other but not fairy necessarily. I doubt highly that anyone could identify beings across the entire range of possibilities. Instead a person would need to specialize and when someone encounters a being they may need to research or ask around across a variety possibilities before you may find what you encountered. And even then you may not have a name for it.
And that's still alright. A personal experience is no less valid just because what you saw or experienced can't be found in a book or wasn't shared by other people you know. I'd suggest (as always) making notes about the experience, what you saw, how it acted, what happened, and so on because that might be useful later in discerning at least the nature of what you encountered. But don't worry that just because you can't find it in a folklore book or grimoire that it doesn't exist. There's a lot more out there than can be found between the pages of books.
*for the record I don't believe they are actually truly unknown. I suspect the knowledge or stories of them have either been lost or is simply not readily available to the person