Brumsic Brandon’s Luther:
http://newsgroups.derkeiler.com/Archive/Rec/rec.arts.books.childrens/2007-04/msg00023.html
http://lambiek.net/artists/b/brandon_brumsic.htm

Morrie Turner’s Wee Pals

http://lambiek.net/artists/t/turner_morrie.htm

If you count ghosts, Andre LeBlanc, a Haitian-American who was also popular in Brazil, worked on such strips as Will Eisner’s the Spirit, Lee Falk and Sy Barry’s The Phantom (which he was reportedly working on at the time of his death in1998) Rex Morgan M. D., Apartment 3G and Flash Gordon. He also illustrated one classic Scholastic book, Snow Treasure by Mary McSwigen about a successful Norwegian attempt to smuggle some gold out of the country before the Nazis found and confiscated it

http://lambiek.net/artists/l/leblanc_andre.htm

I’m absolutely sure there is more but those are three I remember.

EDIT: I feel really really REALLY Dumb. Through Brandon’s Daughter Barbara’s Lambiek.net page I linked through to Jackie Ormes who did Torchy Brown. How I EVER forgot Torchy Brown I do not know:

http://lambiek.net/artists/o/ormes_jackie.htm

They said that Barbara Brandon’s Where I’m Coming From is the first nationally syndicated strip by an African American woman SINCE Torchy Brown. Ah well.