A spinoff from Arrow and The Flash is currently in development, which will see a team of superheroes formed from new and existing characters.
Brandon Routh is set to play Atom; Victor Garber will play Dr. Stein; Wentworth Miller will play Captain Cold, and Kaity Lotz will also have a role (whether it's her Arrow Canary role is unknown).
It's also been said the Arrow/Flash superhero team spinoff will feature three DC Comics heroes who have never been on TV before, and now TV Line may have a description of the characters.
“THE TRAVELER” | Described as a “Han Solo-esque rogue who gets by with his charm, this hero hails from the future, and has journeyed back in time on a secret mission. His razor-sharp wit hides the pain of a man who has lived through serious conflict. He also harbors many secrets, always leaving both his teammates and the audience unsure of his true allegiances.
“FEMALE WARRIOR” | This twentysomething Latina is pretty but unassuming, book smart and socially awkward by day. But by night, when she hears the cry of battle, her fury is ignited and she becomes a fierce warrior — so much so, that sometimes she can become a threat to others.
“MYSTERY HERO” | An African-American male in his twenties will fill the role of a regular, street smart guy who unexpectedly gains powers, and then, as part of the team, regularly quips about the insanity of the situations.
As noted, "The Traveler" could possibly be Booster Gold or Rip Hunter.
"Female Warrior" may be reference to the female Wildcat (or maybe even an Amazon).
The "Mystery Hero" could be Static or Black Lightning.
The Arrow/Flash spinoff has also been said to be adding other characters from the shows (probably Robbie Amell, the other half of Firestorm).
Arrow creators, Greg Berlanti, Andrew Kreisberg and Marc Guggenheim, are putting the series together, which is expected to debut next season/mid-season.