I'm thinking of books like _14_ by Peter Clines, where the residents of a certain apartment building get wrapped up in a strange Lovecraftian conspiracy, or something like _Lost_ where a random collection of travelers wind up stuck on an island unraveling its weird and complicated history.
Both of these follow relatively normal folks with limited resources getting wrapped up in something strange and mysterious with sci-fi or fantasy elements. A key element here is that, while these stories are high-stakes and full of danger, they aren't straight-up horror stories.
This seems to be very common in children's and young adult fiction, but genre fiction for adults is much more likely to call in an expert, or someone who is otherwise exceptional and well-equipped to handle the situation.
by OkapiAlloy