Hello everyone!

The BBEG of our ongoing campaign is not carved in stone yet, so I'm looking for some inspiration. As far as I've encountered them, the overwhelming majority of evil masterminds in pop culture and fiction are male. I'd like to have anything different than that, but at the moment, I can't think of many examples to draw inspiration from.

I don't have a lot of specifications for what I'm looking for. Apart from not being male, they should just be examples of true spite, not someone who can be bargained with. And they shouldn't be the right hand of another greater villain, but stand on their own feet in terms of scheming and orchestrating bad stuff. (So no Darth Vader, but an Emperor. An Empress, actually, or really anything but a dude.) They can come from any genre, media and setting. Favorable if they can pack a punch or two or more, though not mandatory.

D&D has Tiamat and Lolth, Star Trek TNG has the Borg Queen. But other than that, my mind's completely blank right now. I'd really appreciate any suggestions for more baddies to take a look at, characters that help me to get into other evil mindsets than those I'm most familiar with.

Thank you very much!