[Kalimac]

Hmmm, the Faithful Four; Lobelia, Shelob, Ungoliant and Queen Beruthiel. Can't really think of anyone else who doesn't live exclusively in the appendices, but if you don't mind those characters there is always Tar-Ancalime, who wasn't exactly easy to get along with. Odd that all of these villainesses (except for Lobelia, and she's kind of iffy anyway) are queens? Beruthiel and Tar-Ancalime, obviously, and even Shelob and Ungoliant are essentially the ruling queens of their highly unpleasant species. There's no grubby female equivalent to Gollum, and no female Ugluk or Saruman. Most interesting...