I haven't read all 100 stories specifically, but typically they might include tales of haunted houses where strange noises are heard at night, like creaking floors and slamming doors. There could also be stories about ghosts that haunt specific people, following them around and causing unease.
Well, in '100 ghastly little ghost stories', there could be stories about apparitions in old cemeteries. Maybe a figure in white is seen floating among the tombstones at midnight. Some stories might involve ghosts that are seeking revenge for some wrong done to them in their past lives. For example, a ghost of a murdered person coming back to haunt the killer or the killer's descendants. There could also be stories about friendly ghosts that are just lost and trying to find their way to the afterlife but end up scaring the living in the process.