As mentioned above, just about anything tune wise can shoehorn Pinball Wizard lyrics in it, ditto Rudolph The Red Nosed Reindeer.

Of course, other than music to accompany a raffle, the term 'folk' can be loosely applied and indeed is. A ballad about an event in history? Anything from "I don't like Mondays' to "Smoke on the Water" or songs that sum of prevailing social conditions and how people felt about them such as "The Killing of Georgie parts I and II" or "Rocket Man / Golden Brown / Lucy in the Sky with Diamonds / etc"

Not a pair of trousers anywhere near their tits there....