Deadshot, Fate, Darkseid, Firestorm, Cold in that order in terms of pure zoning imo. Deadshot has the most straight forward, effective, and easiest to apply zoning game. Fate's is the most technical imo, a lot of it depends on how easy it is for him to get out the orb based on who he's fighting, that plus his Sinestro like fireball, traited ankhs, push, and F2, he can honestly make it hell for some characters like Robin with bad mobility, but I think Fate gets outzoned head to head by the other characters mentioned except maybe Cold. Darkseid can shut down the other zoners and the omega beams are pretty good. Firestorm has a good fireball and the trap, ex fireball being fast as shit. I agree that Cold isn't as much of a zoner as the others, his strength is more about traps and setplay, along with pretty strong space control, but really lvl 2 trait in the corner = slit your wrists