For those that are still watching and are geeky about Batman, it feels like I'm missing out of stuff.
I'm enjoying the series, or to be more precise I'm enjoying Penguin.
Catwoman is currently Catgirl & The Riddler is the scene of crime investigator, but that's about it.
Are there any other main characters appearing that I've not noticed?
I can't believe I would have missed The Joker.
I've only seen the first 5 episodes (I tend to binge watch after getting a build up on my planner these days).
There have been several attempts to tell the Joker's backstory in the comics, to the point where the idea no one knows which is true has actually become part of the history of the character.
In one of them, he is a failed stand up comedian, who is convinced to help a gang get access to a chemical plant he used to work at, but he gets framed and falls in a vat of acid.
In one of the early episodes of Gotham, Jada Pinket Smith is audition acts for her clubs, and one of them is a stand up comedian, which I think was more a nod to the story than an actual set up, but I think that's the closest to the joker appearing (at least from what I've seen so far).