The question in the thread title is not the same as the one asked in the end of the post.

To answer the former, yes, I gladly read works with non-existent beings. So do loads of other people. A rather big share of Speculative Fiction (the roof category for all of fantasy, science fiction, horror etc.) is about such beings.

To answer the latter, yes, people frequently favor familiar over the unknown. So even on the field of Speculative Fiction, works by authors with reputation for quality output, and fictional beings with some amount of tradition around them, have wider appeal than unknown works.

This is something that every original author needs to accept and work to overcome: to climb out of obscurity and get in the minds of people. It doesn't matter how good your story is if no-one knows about it. And contrary to what many people might think, a work is not its own advert. If the only thing that would get people interested in reading your story is reading your story, you've already lost. You need to actually distribute it and get it in the face of people so they'll read it to begin with.