@AHolyToilet I missed commenting .. not getting notifications I guess. @Bridleton mentioned the ones I know off hand hint wise that have happened but there have been other major hints prior to something showing up in the game.... sounds, thought bubbles, objects and even clothing. This isn't really the thread for it though.
To be more on topic .. I do always think of fairies when I send my sims to the secret lot in Willow Creek. You have the floating light things that swirl around you and the small giggling sounds.. but that has been in the game for a long time. The only other reference that I know of is in that toddler tree house. I do want witches more than fairies but I hope we get all of the supernaturals and various life states we've had in the past sooner or later.