3) Commissioner Gordon
He might often be overshadowed by the Dark Knight himself, but let’s not forget that James Gordon is a damn fine detective in his own right. Sure, Batman is the one who saves Gotham on the grander scale, but Gordon is an effective commissioner and a man of extreme integrity and courageous spirit.
In most continuities, Gordon is a former army veteran who moves to Gotham and becomes a cop. Realizing how corrupt his fellow officers are, he clears up the force from the inside and eventually rises to the top of the pile, achieving the position of commissioner. Recently, Gordon’s own heroic nature was proven when he briefly took on the mantle of Batman, after Bruce Wayne had apparently died. With the aid of a mecha-suit, he struggled to fill Wayne’s boots, but he did some good in Gotham before he returned to his usual career.
The early part of Gordon’s life, where he actually operated as a detective, has often been explored over the years in the likes of Batman: Year One, Batman Begins and, most notably, in Fox’s Gotham, where the young Gordon is played by Ben McKenzie.