A pack of wolves, a parliament of owls, a herd of bison… Should you need to refer to groups of paranormal things, though, what do you say? Traditionally, “coven” is used to refer to a group of witches or vampires, but someone has taken up the challenge to assign words for all groups of beasties.
This is a creative if specious list… I do love the “lunacy of werewolves.”