The Three Henchmen (and Girl) of the Joker

Before Harley Quinn there were many to take the mantle of Joker's #2 (Going in order of the Comics/Movies/Shows).

First there was the recycleable average #2 guy named Bob.
He smokes, he wore shades and a suit, he didn't talk much, he was all an evil villain could want. Joker ended up leaving him behind on their second heist together. He now sits in Blackgate.

Then there was Gagsworth A. Gagsworthy AKA "Gaggy".
He used to work in the circus as the star attraction, the acrobat. Until the circus bought "The Flying Graysons" then he was demoted to be just another clown. Joker was in the audience when Gaggy snapped and killed one of the other clowns during an emotional breakdown. Joker, finding it incredibly hilarious, decided to hire him. They had a good run even, Gaggy was almost like Joker's very own Robin. Until Joker got bored with Gaggy's gloom and decided to cast him out. Gaggy now resents the Joker, as well as Harley Quinn.

Last, but not least, we have Harleen Francis Quinzel (Harley).
Therapist for the Joker until HE ended up getting in her head (and in her knickers). She then becam practically obsessed with him and has been his #2 fan, #1 fan being himself, and became somewhat of an on/off love interest. Unlike most interpretations though I make Harley and Joker's relationship rocky, but not too abusive. He actually cares about her until she screws it up big time, then they're on 'no speaking' terms until he either forgets it happened or just doesn't care anymore.