10 Batman Sidekicks Everyone Forgets
1. Harold Allnut
There's a very, very strong chance that there is precisely one reason that Harold Allnut isn't a well-known member of Batman's team, and that's entirely because nobody wants to try and introduce someone to the name Harold Allnut, as it's something you have to find and then laugh about for five minutes on your own.
Which is really awful, as Harold is the most important Batman figure that nobody knows about. Initially appearing in the Question #33, Harold is the hunchback child of two decidedly awful aristocratic parents, who kick him out for his appearance and mutism. Despite all this cruelty, Allnut spends his first comic appearance saving a child and her mother from a violent criminal, helping them before The Question himself can even arrive on the scene.
After working for the Penguin, the tech-savvy Harold would be taken on by Batman, who saw the cruel way the man was treated by much of Gotham's public, and decided to give him a home and a job in the Batcave.
Harold would be killed by Hush in Batman #618, but has been technically brought back by retcons, as he's alive and well in several newer Batman comics.