DC released over the last few months a new line of comics called The New Age of Heroes. It was designed to showcase top tier artists but the characters are all brand new, barring The Terrifics. The new Challengers of the Unknown book treats the title as a legacy team, so while the concept is nothing new, the members of the new team of Challengers are all brand new.
Back in 2000, DC did something called Planet DC 2000 across all of the annuals that introduced brand new international heroes. Outside of Ishtar, who appeared in the Green Lantern annual and then later the JLA: Gatekeeper mini series, I don't think anyone has done anything with the characters created.