In the comics, Despero has traditionally been an enemy of the Martian Manhunter, Booster Gold, the Green Lantern Corps, and the Justice League.
When Ray shrinks and re-enlarges him during the fight with Despero, Barry comments that he now knows "what Diggle feels like," referring to Dig's frequent bouts of motion sickness resulting from Barry zipping him around at superspeed.
Signage can be seen at the tech convention for Kord Industries. In the comics, this is the company owned by Ted Kord, one of the heroes to take up the mantle of The Blue Beetle. He has been referenced in the Arrowverse from as early as the first season of Arrow, but has yet to actually appear.
Nora Darhk's status as a fairy godmother and marriage to Ray is known to not just the Legends; Team Flash found out at an unspecified time.