Jean Harlow. Dead at 26, probably from excessive hair bleaching. She was funny, sexy, and intelligent. She's one of my favorites.
Deborah Kerr. KYHillChick's most vivid memory of a moment in cinema is being a sheltered little girl from the hollers and watching From To Eternity and the famous roll in the surf. Deb was the one doing the rolling with Burt Lancaster. Dang! That's still a scene. I liked her in everything she did.
Maureen O'Hara. There were darn few women who could stand up to John Wayne's onscreen presence.
The only other one that comes to mind is another of my favorites:
Patricia Neil
an honorable mention goes to Karen Allen
I never saw her in anything I didn't like.