With two already existing DC comic shows and one to come, as well as constant references to other superheroes in the DC universe, big things are sure to come from the CW and DC Television. Legends of Tomorrow will premiere in a few weeks, with Flash and Arrow returning from winter break, and I bet that more heroes will be introduced over the next few years.
I can think of several easter eggs and references over the course of the combined 4 seasons of Flash and Arrow. Like when Barry, Cisco, and Caitlin first entered the time vault in season one, and Gideon stated that Barry was Chief of Police in the future, and that he would become a founding member of the Justice League. I also remember seeing a Batman reference on Dr. Wells' future newspaper. There was an article in the paper about Queen Consolidated merging with Wayne Tech, the family company of Bruce Wayne, aka Batman.
Green Lantern has also been referenced twice if I remember correctly. In season 1 of the Flash, when Barry tries to send all of his captured metahumans to Lian Yu, Oliver Queen's private prison, they head to Ferris Airfields to catch an ARGUS plain. Leonard Snart, aka Captain Cold, asks about the closing of Ferris Air. Barry responds by stating that they shut down because one of their test pilots went missing, a direct reference to Hal Jordan, aka Green Lantern. Also, on the season 4 premiere of Arrow, you can briefly see a man in what looks like a pilots jacket that says Jordan... Hal Jordan?
Several references to Coast City also show up in both shows, which makes me feel that Green Lantern will definitely show up at some point. And I remember one specific episode of Arrow where Diggle and Oliver recite a poem that name drops Solomon Grundy.
I hope that one day, The Justice League and others make their way on to the CW, starting with minor heroes like Cyborg, Nightwing, Aquaman, or Shazam. This is totally, possible, considering that smaller heroes that The Canary, Atom, Firestorm, and both Hawkman and Hawkgirl have made appearances on the shows. AN dwith Legends of Tomorrow premiering soon, that lets me know that DC is open to a superhero team show, like possibly Justice League, or maybe even Teen Titans.