8) Mister Terrific
While Echo Kellum’s recurring character on Arrow, Curtis Holt, is mostly based off Michael Holt who only debuted in 1997, the original version of all-round renaissance (super)man Mister Terrific first appeared in 1942, which sneaks him onto this list.
After appearing several times in Arrow season four, Curtis will be made a main character for season five. Given that, it is more than likely that he will take up the identity of Mister Terrific on the show fairly soon. In case that isn’t the plan, though, he really should. Despite the Terry Sloane version of the character having been around for so long, the hero has never appeared in live-action before now – a quick reference in Smallville has been the extent of it so far.
A genius level intellect as well as an Olympian athlete and master martial artist, Curtis’ super alter ego would definitely give Green Arrow a run for his money.