To be fair, it might actually be a good thing that there weren't female minority characters back then, as minority characters tended to be horrible things. Do we really need a female Apache Chief, El Dorado, or Samurai (as from The Superfriends)?
But it is rather impressive how difficult it is to think of even just good female characters. I think I remember a few good ones, however.
While not a lead character, I recall Princess Zelda from the old Captain N show was fairly admirable. They took the "rescue the princess" but from the first two games and turned her into an adventurer herself who generally seemed on equal footing with Link. Though she did fall into the stereotype of the responsible woman who is the love interest of the irresponsible man.
Gadget Hackwrench, from Chip N Dale's Rescue Rangers, though again not a lead character, was one of the first smart, mechanically savvy female characters I can remember. She was stereotyped, but a lot of guys have filled that same stereotype, I think.
Then there was Gosling from Darkwing Duck, who while not the title character, was usually more competent (and adventurous) than her father.
Gi and Linka from Captain Planet weren't that bad... though Wheeler sort of had a lead character role, I guess, since he was American, and Linka was thus the sort of default love interest (because you totally couldn't have him go after Gi, for whatever reason).
Demona, from Gargoyle, was evil but she may well have been the most awesome villain of my childhood memories. And even as a villain, a lot of her evilness resulted from her desire to protect her kind (as sort of good intentions gone astray situation). And Elisa Maza, though again not a main character, is actually still a rather impressive character. Sort of the Scully of the cartoon world.
She-Ra was a fairly strong lead character; I can't remember ever watching that show, but then I also can't remember watching He-man.
Annabelle, from Eek! the Cat, is one that I'll always remember, but I can't actually remember much about the character herself...
Oooo, Rainbow Brite! Or... should I be ashamed that I was a huge fan of her when I was young? Anywho, she was a fairly strong character, from what I remember, though perhaps the general setting of the franchise leaves something to be desired?