She has done covers for Black Mask, Dime Mystery, Detective Tales, and New Detective. Also Rangeland Romances, All-Story Love, New Love, Love Book, Love Short Stories, Love Novels, Romance, and Thrilling Love magazines.
In addition, she did interior illustrations for Argosy magazine.
Her website at http://gloriastollkarn.com/ has some of her cover artwork and contact information.
Surely a worthy candidate for guest of honor at a pulp convention.
Gloria Stoll Karn appeared as a Guest of Honor at Pulpcon 30 in 2001 but you are right, we should invite her again. There are not too many pulp writers and artists left and we should take advantage of inviting her again. She lives in Pittsburgh which is fairly close to Columbus, Ohio.
I'm just back from Pulpfest 2017 and they held it in Pittsburgh, Pennsylvania. Since Gloria Stoll Karn lives nearby she was the GOH. In her nineties she was fantastic and gave a witty interview with David Saunders.