The Flash Season 2: 7 Theories On The Man In The Iron Mask's Identity
6. Earth-1 Hunter Zolomon
Jay Garrick doesn't exist. It's a name ostensibly made-up by Hunter Zolomon, the real person behind Zoom, although deeper connections may yet be revealed.
There was a clue to this on Earth-1, when 'Jay' revealed his doppelgänger to Caitlin, except that he went by the name Hunter Zolomon. Although that reveal has already factored into the Zoom character and Barry's efforts to stop him, they haven't revisited the actual person that Earth-1 Hunter is. Why?
It might be that he really is just a nobody, and isn't of importance beyond establishing Zoom is not Jay, but could Zoom have actually went so far as capturing Hunter? There'd need to be a very good reason for doing so, such as him having powers, but he would fit with the shot that shows the man in the mask having blonde hair if nothing else, and Zoom might have taken him prisoner as some sort of contingency plan.