Currently(or soon to be) Reading: Absolute Power, Batman/Superman: World's Finest, Birds of Prey, Green Arrow, Green Lantern, Justice Society of America, Shazam, Titans, & Wonder Woman.
As Hanna Barbera's El Dorado? Or as Young Justice's Eduardo Dorado? Sadly we didn't get an Ultimen Dorado.
Or maybe a hybrid/combination of both? (actually what I would love to see for all the HB creations)
Harley Quinn, Jimmy Olsen, Harrison Wells, Andrea Beaumont.
Some sources claim that Olsen first appeared in the comics (in a nameless cameo), although his first name-referenced print appearance did come after the advent of the radio show.
Perry White, however, definitely made his debut on radio.