Sandman spinoff comics Books of Magic/Books of Faerie had mortal queens, though differently, IIRC. Titania turned out to have been human, a servant of the old queen who stole some items or something. Molly might have replaced her, though she might have had her own faerie heritage.

Molly aside, this is queen as in wife of Auberon, not as sovereign as she appeared in a lot of Sandman or Gaiman's Books of Magic.

Strange and Norrell had human magicians as lord of faerie, most obviously the Raven King.