Missy Elliott- She's actually had a "career" in that she's consistently dropped music. She has crtically acclaimed albums. Say what you want about her skills or lack thereof, but she's made some dope music. Missy Elliott changed the perception that a female had to be gangsta or sexy to be successful. If Queen Latifah's legendary, you have to co-sign Miss.
Lauryn Hill- This goes without saying. She came out with one of the greatest albums in any genre in Miseducation of Lauryn Hill.
Queen Latifah- She's made some classic music over the years and IMO, "U.N.I.T.Y." is potent enough on it's own for her as a legend.
MC Lyte- See the first statement about Queen.
Roxanne Shante- She's a pioneer
Lil' Kim- She did a lot in terms of a female being open about sex in Hip Hop
Foxy Brown- see Lil' Kim
Da Brat- First female rapper with a platinum plaque.