The obvious ones, of course, are SUPERGIRL and BUFFY THE VAMPIRE SLAYER. Buffy started as a feature film before coming to television, where it ran for six years, so lots of eps and at it’s best, it’s a really good show. Supergirl was a feature film back in 1984 but it’s pretty terrible — mostly notable for its camp value. The CW Supergirl is a lot better. AGENT CARTER is a fun show.
If your girls aren’t ones to turn their nose up at older pictures (and some younger ones will do), ZORRO’S BLACK WHIP was a cool serial from 1944 in which the Zorro character (he’s never actually called that) is killed near the beginning and his sister takes over the identity, battles the bad guys and saves the day. TIGER WOMAN, made that same year and also starring Linda Stirling, has the title character battling evil-intentioned oil men in South America. You may be able to find these on Youtube.
Sheena, who was the most successful of the female versions of Tarzan, has appeared in two tv series, one in the ’50s and one from 2000–2002, and a 1984 feature film starring Tanya Roberts. I wrote a pretty slim and sad puff-piece about them here a few years ago:
In the beginning, there was Sheena. As a child, Sheena was orphaned when her explorer father died while trekking…comicscomments.blogspot.com
I’m not a big fan of any of the Sheena projects but the Sheenas are all well-cast.
RED SONJA from 1985 is Marvel’s female Conan character. It’s not a great movie but it’s very much of that ’80s mass-appeal milieu some people like. Arnold Schwarzenegger plays a part in it, sort of trying to help send off what was supposed to be a series of flicks but never went any further.
I’d strongly recommend the 2007 tv remake of BIONIC WOMAN. It was very uneven in terms of tone but quite good (and significantly darker than the original). Alas, it became entangled in a writer’s strike, was cancelled and has fallen into obscurity (though the home release is, as far as I know, still in print). A short piece I wrote about it:
This was written as an informal Facebook post, so it's probably not up to my usual standards here but the show is a bit…cinemarchaeologist.blogspot.com
(And, of course, there’s the ’70s original of the same show and the Lynda Carter WONDER WOMAN, both of which ran three seasons, but if your girls are voracious when it comes to this material, they’ve probably seen those.)
Another is the 2002 adaptation of BIRDS OF PREY. It was a tv series based on an often-very-good comic and only ran one season. Barbara Gordon, formerly Batgirl, is left disabled by the Joker and launches what becomes a team of female characters from the Batman universe. I’m not a big fan of the series but it’s another obscure one, so less likely to have been seen.