Most notably DC's longtime golden boy, Geoff Johns (though Scott Snyder may take that title), who is a frequent collaborator of his. To be honest, I time it was time for Ethan to go focus on his creator-owned projects because he gave fourteen years of his life to the company. He deserves the success he is getting with his crowdfunding efforts.
Also, there is something about the culture of DC that makes it more approachable than Marvel. Say what you want about Dan Didio, but he is a guy who wants you to read his books with the passion and energy to back it up. Similarly, Jim Lee is pleasant to the fans with a passion for the medium. Meanwhile, I really don't get that vibe from Marvel and miserable assholes like Tom Brevoort who seem like they're trying to turn the house Stan built into an IP for Disney's marketing machine. They are riding the coattails of the MCU and it is really the serpent eating its own tail since most of the MCU adapts much of its material from the comics prior to 2008.
In any case, I have little doubt that Dan, Jim, and Geoff could convince Ethan to freelance for them at some point in the future.
Anyone want to bet that neither title makes it to issue twelve?