Any one of them. Brady makes WRs better, by and large - the only limitation is that they have to be smart enough to handle a complex playbook full of option routes. OBJ and DeAndre Hopkins would be great here too, and I'd love to see what Brady would do with a receiver like AJ Green. If there's one guy that I think would disappoint here, it's probably Julio Jones, but mostly because I think he's overrated in general and he doesn't really play to Brady's strengths. He'd do very well here because he's too good to do badly anywhere, but I think he'd produce less than he does in Atlanta.
As far as one WR who I think would particularly excel here, I'm going to go with Antonio Brown. Exceptional route-runner, great hands, tracks the ball well downfield, makes contested catches, YAC machine. I'd take him over Hopkins both because I think he's a bit better in general and because I think his strengths are a bit more aligned with what's traditionally worked for Brady. Compared to Hopkins, Brown gives up a little in height and a lot in arm length and hand size - as a result, Hopkins is better at making contested catches with minimal separation. Brown, OTOH, has better agility, burst, and speed. That makes him better in a quick-strike passing offense, I think, and his hands are almost as good as Hopkins' despite being much smaller. Re: route-running, they're probably 2 of the top 5 in the league, so pretty much a wash there. I think Hopkins is a better option for maximizing the production of a QB who lacks a bit in precision or decision-making. It's easier for a QB to all (or close to it) of what Hopkins has to offer, whereas Brown has a higher ceiling but the QB has less margin of error when throwing to him. If your QB is Brock Osweiler, you're probably better off with Hopkins than Brown. If your QB is Brady--a guy who's never relied on big-bodied, huge catch radius and/or jump ball receivers, and instead has got the most out of Troy Brown, Welker, Edelman, and Amendola--I think it's fair to say that he could get the most out of AB. You could maybe make an argument for taking a big, versatile, downfield threat like AJ Green just to create more variety across your WR corps, but I'd be more inclined to just take the most talent and challenge some team to try to cover Brown, Edelman, Gronk and Amendola.
Chad Johnson was the exception. His success came entirely in a system where he was operating in one of the simplest offenses in the NFL, which required him to make basically no reads.
