I think the "eco terrorist" version of Ivy is just about the only Gotham villain worth using in Super stories. None of the Gotham rogues are powerful enough to provide a real challenge to Clark, but Ivy does at least bring in the "why aren't you doing more to save the planet?" topic, in a way that Clark's own rogues don't.
"We all know the truth: more connects us than separates us. But in times of crisis the wise build bridges, while the foolish build barriers. We must find a way to look after one another, as if we were one single tribe."
~ Black Panther.
I could see Riddler. Throwing out Riddles to confuse Superman.
Penguin. Mob boss type.
Ras Al Ghul. He would be pretty equivalent to Lex.
ZZaxx (Sp?) Deranged hitman who marks himself. He would just be throwing out to Superman, "I killed a guy and you couldn't stop me.
I think restorative nostalgia is the number one issue with comic book fans.
A fine distinction between two types of Nostalgia:
Reflective Nostalgia allows us to savor our memories but accepts that they are in the past
Restorative Nostalgia pushes back against the here and now, keeping us stuck trying to relive our glory days.
Freeze, Clayface, Scarecrow?
I think Bane could easily become a formidable foe for Superman. Just get a hand on some of that Kryptonian DNA and mix it with his venom juice...BANG! Kryptonian strong.
Scarecrow. Could maybe do something meaningful with the whole “hope” part of Superman by setting him up against a foe enamored with fear.
For when my rants on the forums just aren’t enough: https://thevindicativevordan.tumblr.com/
Yellow Lantern Scarecrow. I thought that was a cool concept.
I think Toyman and Ventriloquist should be fused together. Superman facing an oldman full of anxiety about the "deepstate", and controlled by an animatronic toy he built.
Harley did a stint in Metropolis in her first solo series. She had a secret identity, a job at the Planet and dated Jimmy while causing chaos across Metropolis. She's no serious threat to Superman, but she was a lot of fun.
Mr Freeze might be able to slow him down depending on how modified his weapons are. The cold as a contrast to his heat vision.
I like the idea of eco-terrorist Poison Ivy. We know that she can control him if she gets her hands on Kryptonite.
Scarecrow might be able to at least cause him some trouble if he scares enough people. Acting as more of a chaos agent.
Joker might be a serious contrast to his optimism about humanity. The cynic versus the optimist. Again, a chaos agent in the same sense that Scarecrow would be. But not a serious threat to him personally. It's more like the threat that he poses to everyone else just to get Superman's attention.
Ras would be interesting as sort of "the only person on Earth more powerful than me" kind of way. But Vandel Savage fits that role better IMO.
Deadshot could be like a Terra-Man depending on how his weapons are modified. Smallville did this.
I don't see the others even being all that interesting up against him.
Assassinate Putin!
None of them would fit into Superman's world.
And Superman's world doesn't need any of them.
All it needs is more consistent development and exposure for any and all Superman rogues not named Lex Luthor or General Zod.