Tonight's episode, which featured Flash, Cisco, and Wells (from Earth-2) traveling to Earth-2 featured some cool Easter Eggs. When they first cross over, as they're in between dimensions, we see flashes of a Green Arrow (that doesn't really look at all like Amell, but could be... it was quick so hard to tell), the Flash from the old '90's TV show (John Wesley Shipp, who plays Barry's father on this show, which I suppose definitively links the old Flash series as a part of this multiverse), and Benoist's Supergirl (foreshadowing the upcoming crossover with Flash, and which seems to confirm finally that Supergirl does indeed occur in a different reality from the CW DC shows). All very cool. I'm just wondering who that other Green Arrow might be... We also saw Gorilla Grodd, Jonah Hex, and a Legion ring.
Be interesting to see what comes of it all. We know the Supergirl, Gorilla Grodd, and Jonah Hex stuff will all happen soon, and the Green Arrow may be the future version from an upcoming episode of LoT, but I'm most interested in the Legion ring.
Also, Earth-2's versions of:
Leonard Snart (presumably) is mayor of Central City
Floyd Lawton/Deadshot is a cop who is a terrible shot (cool to see him back)