The internet exploded a couple days ago when a FOX CEO said they'd consider the possibility of a Gotham spin-off. I feel I have to say, that I don't think we'll get a Gotham spin-off, at least not for a couple of years. And I do not think it is the best idea, mainly because I had a very hard time coming up with ideas for one. But it could happen, and I am really interested in the idea, so I did quite a bit of research and came up with these ideas.
Renee Montoya and Crispus Allen/The Question and Spectre
At first glance, you may think this would be a stupid idea, but hear me out. Detectives Crispus Allen and Renee Montoya are not main characters on Gotham anymore, and what I think happened with them is that they moved to another city. In the comics, Renee Montoya was once the Question. Crispus Allen became the Spectre for a small time. What if a there was a show centered around Montoya and Allen, had Montoya become the Question and Allen Spectre? The show would be very different from Gotham, and might appeal to a bigger audience. A show about just Montoya and Allen wouldn't be horrible, but I think The Question and Spectre would be much better.
Okay, here's where I didn't have the greatest ideas. The Riddler is one my favorite characters on Gotham, and I think his story is very separate from everyone else's. His story is connecting to the Penguin's, and his is connected to everyone's story. I think it would almost be better for the development of the Riddler, to have his own show. He is one of the best on Gotham, but is the most underused.
Zsasz is a very dark character. He goes out and kills people, then he cuts a tally onto his body to add on to how many people he has killed. This show would center on Zsasz moving from Gotham, or being in Gotham, and doing whatever he does... which I have no idea what that is.
The Red Hood Gang/Red Hood
In season 1, one of the best episodes was the one with the Red Hood Gang. Whoever wore the red hood, got to lead the group. At the end of the episode, all members of the gang died. But some young kid picked up the hood and shot an imaginary gun. I think a TV show about this young kid (maybe a different version of Jason Todd?) running amok in Gotham, or another city wouldn't be that bad of an idea.
Firefly is a fairly new character on the show. She was badly burned but alive, and was going to be worked on. I think Bridget Pike will become a much bigger character in Gotham in the future, and a good friend of Selina Kyle. The idea of this series, is that it follows Firefly going around town being an anti-hero doing good and bad things.
That was my list. I know that none of them are great, but I really wanted to come up with some, and these were the results.