(This might be a question that was already but... sorry) I can't choose, I mean I love all of them but the ones that stand out to me are Queen Chrysalis, Night mare moon, and Discord. I would have to say out of those three that my favorite is Discord. (SPOILER!!!!!!!!!!!!) But he isn't really a 'villain' now.. So I would go with Night mare moon. Who is yours? Comment below your answer and have a good rest of the day/ night.