Professor Zoom
In "The Golden Age of Justice!", Jay Garrick is shown to be a long-time member of the Justice Society of America as the team battles their old foe Per Degaton. In "Sidekicks Assemble!", in a flashback, the Barry Allen version of the Flash appears in a cameo with the Justice League. In "Requiem for a Scarlet Speedster!", Jay Garrick, Barry Allen (this time voiced by Alan Tudyk) and Wally West (voiced by Hunter Parrish) all appear, as the three Flashes and Batman take on Professor Zoom.