/u/itsallfolklore may be able to provide you with a comprehensive answer that handles folkloric material that was accessible to the general population and 'campfire-esque' scenarios (though you may want to be a little more specific, medieval Europe spans a diverse continent and 1000 years of history).

For my part, one of my areas of interest/study involves monastic accounts of the dead. While these do not exactly serve the same function as the genre of campfire tales, to instill terror as entertainment, the cautionary nature and admonishing content of tales involving the dead assume a certain degree of horror and fear that served the purpose of the author well. Not to mention, many of the cloister hauntings and dormitory invasions characteristic of monastic ghosts are chock full of all sorts of anxieties common to abbots and monks intent on keeping their community pure. I have discussed these stories, and some of my favorite examples, previously.

Some of the elements contained within these stories, I am thinking particularly of the wandering corpses of William of Newburgh, may reflect or hint at more popular anxieties and fears about the dead, but these are, of course, still filtered through the lens of an Augustinian canon writing a history and attempting to demonstrate the gravity of the times in which he lived. At the very least though, William does seem to be drawing off popular fears about the dead and what happens to a corpse postmortem.

Sadly, everyday folks have not left us records of the stories they might have told on a blustery winter's night in northern England, so I apologize that I am not able to offer you anything in that department. On that point one of the folklorists here may be of better service to you. But in the meantime, enjoy some monastic ghost stories! They're entertaining if not anything else.