The Marvel Cinematic Universe's Infinity Saga saw the establishment and assemblage of Marvel's mightiest heroes, culminating in nearly every one of them coming together in the climax of Avengers: Endgame. However, while the past 10 years of Marvel Studios films have covered the rise of the heroes, it may soon be the villains' turn.
In the comics, the aftermath of the company-wide crossover Onslaught event saw the Marvel Universe in a state similar to the one the MCU is in now. With some of Earth's Mightiest Heroes like Iron Man, Thor and Captain America no longer defending the planet, a new team stepped forward to replace the Avengers: the Thunderbolts. The twist, of course, was that the super team was actually comprised of villains in disguise, and the MCU already has the perfect foils to fill the roster.
Baron Zemo
Not seen since Captain America: Civil War, Zemo is one of the few MCU villains to survive through the end of his debut movie. Throughout the film, he established himself as possibly the MCU's greatest mastermind, enacting a complicated plan involving countless moving parts that nearly succeeded in tearing the Avengers apart. Next set to appear in The Falcon and The Winter Soldier, there's nobody more deserving of the leadership role than Zemo himself. It also helps that the character is intrinsically tied to the Thunderbolts team of the comics, leading it both originally and in various incarnations thereafter.
Abomination
Possibly the most hotly anticipated MCU villain return is Abomination, although Marvel seems to have a hard time finding just the right play to reintroduce him without a solo Hulk film. Debuting in The Incredible Hulk, Abomination was like a demented Captain America who Hulked out after getting hungry for more power, and since the film's conclusion, he's been imprisoned by the government without further issue. It's hard to imagine better muscle for the team than Emil Blonsky, and Tim Roth would be a stellar addition to a Thunderbolts cast.
Batroc
While a lot of casual moviegoers may barely remember Batroc from his all-too-brief scene in Captain America: The Winter Soldier, comic fans remember him fondly as a cool, modernized update to an otherwise silly concept. Batroc is known as "The Leaper" for his frog-like jumping ability, though in the MCU, he was a kickboxing terrorist pirate who held his own against Cap. He was last seen in interrogation after being captured in Algiers, and much like Abomination, he's presumably been sitting in his cell twiddling his thumbs until the government asks for a favor.
Ghost
Another member of the team straight from the comics, the MCU's Ghost may seem like a puzzling choice for the supervillain team given her sympathetic motivations. Throughout Ant-Man and The Wasp, she sought a cure for the condition that caused her to phase through solid matter, and when the heroes agreed to help her find one, she seemingly found redemption. However, curing Ghost's condition completely fell to the wayside after The Snap. Although Scott Lang went to the Quantum Realm to help cure Ghost, when he emerged five years later to find half of all life dusted away, he didn't seem to give it another thought. It could be that the villain is looking for revenge or simply needed to find a certain evil genius to help cure her.
Bullseye
This pick is the longest shot of the bunch, but probably the one that would elicit the biggest fan reaction. While the MCU films seem to largely ignore their small-screen counterparts, hope always remains that the whole universe will tie together in a way that feels more substantial than a brief wink or an Easter egg. Using the maniacal sociopath Benjamin Poindexter from Season 3 of Daredevil would go miles in terms of making up for the neglect and subsequent cancelation of the Marvel Netflix series.
At first an FBI agent who embraces his dark side to work for the crime boss Kingpin in a plot to ruin Daredevil's reputation, Bullseye was the centerpiece for innumerable scenes that showcased his deadly efficient accuracy. Whether he was ricocheting bullets to shoot around corners or embedding office supplies into drywall, Bullseye proved himself to be a supervillain-caliber threat. Plus, the character of the comics always had a fun dynamic on the Thunderbolts team, somehow managing to make all the other bad guys look downright moral by comparison.