When I really want to scare myself, I imagine some rogue planet that got flung out of a system and is in the middle of one of the “voids,” absent any parent star. How dark and hopeless that would be (not to mention extremely cold.)
Recently I read (or skimmed) an article that claimed there were rogue planets out there with liquid water on or near the surface (from internal heating I suppose). Wouldn’t be good for humans, but it might be okay for some forms of life. If you lived there, you’d think it was just peachy.