I'm not very familiar with Spiderman's rogues gallery beyond the ones who've already been in movies but I had this premise for a Batman movie I recently came up with and I think it could potentially be very good.
So, my idea was: Let's go with clayface. Now, Clayface is a disgraced actor who, under some circumstances I'm not gonna reiterate, turned into a shapeshifting monster. And this, to me, connected to a bunch of potentially interesting approaches: For one, he's an actor and we're making a movie so it's an opportunity to take a more meta approach to the idea of film adaptions. A-and of course the death of Batman's parents that lead to him taking up vigilantism happened after they saw a movie in a theater. And that's where it all kinda connected: We're making a movie, our antagonist is an actor and our protagonist took up the cape after having seen a movie. There are sort of naturally occuring themes there that could be used to examine the idea cinematic Batman adaptions on a meta level.
So, Clayface, or Basil Karlo, if you wanna use his birthname was starring in monster movies in the source material. But let's ignore that and say that our Basil was starring, of course, in a well known superhero movie. In the comics what drove him over the edge was his most famous movie getting a remake, starring a different actor, we're gonna run with it. The hero he's played is getting a new movie where he's played by a different actor. An evil scientists gives him a serum that turns him into... well, Clayface, a shapeshifting monster made of clay. Now, bear with me, a man made of clay is conceptually rather close to that of the Golem from hebrew mythology so let's say that plays into it: He's being manipulated by the mad scientist to do his bidding, with promises that he can be a star again, that with his new powers he could play any role he ever wants and the only thing he needs to do is follow his orders.
But we do want to make Karlo a tragic character. After turning into Clayface and taking on various different identities he's coming closer and closer to losing his own identity. The actor is becoming fully assimilated by his roles, meanwhile the public is forgetting more and more about the real Basil Carlo, his old role now being more associated with the actor who was cast for the remake. Swearing revenge he goes on a killing spree of all the people involved with the movie. Batman, of course, trying to stop him. Now, Clayface was, of course the star of the movie he saw before his parents died (Yes, canon says it was a Zorro movie, again, let's take some liberties here) so trying to find the identity of the murderer means he has to retrace his own past. I'm thinking this version of Batman has been doing his thing for a while at this point. I wouldn't mind it being the Affleck one, actually. That could be an interesting way to reexamine previous cinematic incarnations of Batman. Let's say, young Bruce Wayne, still trying to figure out his identity relied strongly on absurd and extremely specific gadgets like the Adam West one. Slightly more experienced Batman employed theatrics like Burtons and Schumachers interpretation. Older Batman took up a more practical, tactical, almost militaristic approach like the one we saw in the Dark Knight movies. And current Batman is close to descending into the ruthlessness and paranoia the version we saw in Batman v Superman, but not quite there yet, not pushed over the edge by the arrival of Superman yet.
So, we have those two characters, protagonist and antagonist, struggling with the ambigouus nature of their own identity, headed for confrontation. That final confrontation, the climactic fight, would be in the very movie theater where it all began. Big action scene, Batman having to use the approaches of all of his previous incarnations to defeat Clayface. The cinema catches fire, as they fight, Batman manages to get out, Clayface, despite Batman trying to save him, dies, turning into a perfect clay statue, once again, one last time, taking the form of the man he used to be, Basil Karlo. Shot of the burned out theater, long, slow tracking shot through soot covered corridors, ending in a room with single role of film, that was, as if by magic, left intact. Zoom onto the label. Clear letters displaying the title
"Persona
by Ingmar Bergman"
roll credits.