According to Deadline Thursday evening, the CW are in the early stages of development of an untitled new DC superhero team-up show spinning out of the CW's Arrow and The Flash, with Brandon Routh, Victor Garber, Wentworth Miller, and Caity Lotz starring.
Routh would reprise his role as Ray Palmer/Atom, with Garber reprising his role as Dr. Martin Stein, and Miller returning as Captain Cold. It's unclear as yet what role Lotz will play, as her character Sara Lance/Black Canary was killed off in Arrow.
Deadline reports the series will also star "three major DC Comics characters who have never appeared in a TV series." Taken literally ("appeared," rather than starred) that would remove a fair amount of characters considering the various DC heroes that were featured in Smallville during its long run, not mentioning the characters in upcoming shows like TNT's Titans and CBS's Supergirl.
The show will reportedly be developed for a possible straight-to-series 2016 mid-season replacement by Arrow creators Greg Berlanti, Andrew Kreisberg and Marc Guggenheim.