How about The Shredder as Marvel's Namor, as actor Brian Tee says he wants to play The Sub-Mariner?
It was previously thought that Marvel Studios didn't have the rights to Namor, which were at Universal, but back in June saw Chief Creative Officer Joe Quesada tell Kevin Smith that as far as he knows, they do.
Here's what Brian Tee, who recently starred in TMNT 2, has to say about potentially playing Namor (via Screen Rant):
“You know what’s funny is my career I’ve kind of played villains, guys with attitude, guys with chips on their shoulders, um, in reading the comics books and being a fan of Namor, that’s kind of this guy’s persona. Even though he’s a hero or a quote unquote good guy. He’s kind of a bit of an anti-hero with a bit of an edge, and I feel like I kind of fall in that line, especially with other things that I’ve done. So that’s the kind of aspect that I would love to bring into Namor. He’s not just like a good guy, you know, he’s definitely got some faults of his own, but I think when it really boils down to doing the right thing he will, and you know it’s Namor, it’s Marvel, it’s the first Mutant, it’s everything you can kind of dreamed of as a kid and wanted to portray, and so I would absolutely love and be honored to play him if the time does come around, and I thank you guys for the movement!”
It's possible that Universal may hold the distribution rights to Namor, as they do for the Hulk (which is why there hasn't been a solo Hulk movie since Disney bought Marvel). It's also possible that Namor might fall into the realm of being a shared character, similar to how Fox and Marvel both used Quicksilver (Fox can use Scarlet Witch, too). That said, Namor is a part of the Marvel Comics Illuminati, and Benedict Cumberbatch did just mention the possibility of the Illuminati in Doctor Strange 2, so Namor can't be ruled out in the MCU.
Regarding Brian Tee playing Namor, we can probably forget about his Agents Of SHIELD appearance as it was pretty minor (one episode where he was killed off).