If I can add someone to your list, Jean Colter. A tall woman with straight black hair. Dresses plainly. A no-nonsense and methodical 40ish mechanical engineer who is well aware that her skills are not primarily political so tries to avoid taking sides, and gets extremely annoyed when people break things carelessly or especially if they do it deliberately. In the draft novel of mine in which she appeared in she foiled an industrial espionage plot to blow up a refinery, then got framed for trying to do the thing she just stopped.
I've got far more detail on her as an original character, but this is probably not the place for it.