3) Kid Flash (Wally West)
Even more so than Roy Harper, comic book fans have seen Wally West grow up over the decades. He began life in 1959 as the kid sidekick of Barry Allen, the second Flash. After Barry’s death in 1986, however, Wally had to step up to the plate and become the third Flash. He went above and beyond in his time as the Scarlet Speedster, serving on the Justice League for over twenty years until Barry was resurrected.
As such, Wally is possibly more associated with the Justice League than the Titans, due to his long-standing place on the team in the comics and his status as a founding member in the popular Justice League animated series. But he was a Teen Titan to begin with and, as one of the team’s founding members, is one the most significant, too.
The classic Wally wasn’t around for The New 52 – where Wally West II was introduced instead. As of DC Rebirth, however, Wally was able to escape from the Speed Force (making him the only hero other than Superman to remember the pre-Flashpoint timeline) and he’s currently back where he belongs: as a member of the Titans.