OK. I've got a theory since we have the Golden Age Flash already an integral part of this current season 2 of CW's hit show The Flash. Theoretically, on Earth 2 they have more heroes than our friendly Mercury outfitted Golden Age Flash Jay Garrick. I'm guessing that we will see a Green Lantern but not our current list of umpteen members of the Green Lantern Corps. I've got a sneaky suspicion we're going to see the original Green Lantern Alan Scott.
The Alan Scott Green Lantern was introduced in 1940 during the Golden Age of comics in All-American Comics #16. Alan was a founding member of the Justice Society(the Golden Age predecessor of the Justice League) and starred in 3 main books at this time as well as making appearances in others. Alan's powers were based off of magic rather than the science based rings of the Silver Age and later Green Lantens. Great character who fought some really great villians including Solomon Grundy and Vandal Savage(the big villian in CW's Heroes of Tomorrow).
I foresee the magic of Earth 2 being brought around as we've not only seen Jay Garrick's Golden Age Flash but earlier in the season we saw the Golden Age Atom AL Pratt on the Flash. We saw The Spectre on Constantine along with Dr Fates helmet. And of course Heroes of Tomorrow's own Hawkman was a JSA member. It's also been rumored that we will be seeing the Golden Age Sandman on the CW shows as well. This is getting to be really exciting as we may even see a full on episode of the Justice Society in action. I think it will start off with Green Lantern Alan Scott and I can't wait!