most of them (sixteen?) are just random questions about characters who happen to be villains: for example, How tall is Galactus?, What did Mayor Wilkins do to Mr Trick?, Did Solomon Grundy get his name from the nursery rhyme?, Who controls the Watcher in the Water?;
eight are ID questions (three story-ID, three character-ID, plus a couple more without ID tags), but I doubt "this story had a villain in it" is really a helpful distinction for an ID question, not enough to warrant being reflected in the tags;
two actually are about villains in general - Why don't more villains die/become crippled? and Which Sci-Fi work introduced the idea of "Mad Scientists as villains"? - but again, I'm not sure if "villains" is a sufficiently well-defined or interesting topic to be worth its own tag.
Do we need this tag at all? If so, which questions should we be using it on?