At the end of Ant-Man And The Wasp: Quantumania.
The time traveler villain looks pretty good, being reprised by his actor from Loki, Jonathan Majors. However, he isn't the only time traveler to menace the Avengers. In fact, there are tons of such adversaries all over comics. Some of them might bring fans insight into where the MCU incarnation of Kang will go.
Doctor Doom
Doctor Doom is the swiss-army knife of comic book villains -- he's done basically everything he can in his quest for world domination. This includes time travel, which he's done for both leisure and conquering purposes.
Doctor Doom has invented a device called the Time Platform that allows him to move through time. He's integrated this technology into his suit, allowing him to travel at will and attempt to conquer the past. He's even butted heads with Kang himself, and may even be a distant relative. He's not time themed, but he has plenty of chronological abilities.
The Organization
Donald Duck has a long and weird history, especially in comic books. European comics have given Donald lots of wacky adventures, including the Paperinik (Duck Avenger) comics where he becomes a superhero in the future. During these adventures, he clashes several times with the time travel-obsessed Organization.
This shadowy future cabal consistently attempts to use time travel to take over the world. Their operatives usually consist of muscular cyborgs like Odin Eidolon, the Gryphon, and their most famous agent, the Raider. These villains will attempt to change the timeline but are usually stopped by the main hero.
Armaggon
Armaggon isn't as well known as the biggest Teenage Mutant Ninja Turtles villains but he's made a lot of appearances. This shark originally debuted in the Archie comic series based on the turtles as a mutant from the future. While he's appeared in most modern Turtles media since then, time travel usually gets left behind.
This is a shame because it was a big aspect of the character in his debut. Given he was from the future, he knew how the heroes fought before they ever encountered him. The storyline he was involved in also contained a nice moral about global warming, as the future he came from was flooded. These aspects could possibly be toned up in any future appearances.
Chronos
Given that he named himself after a God of Time, one would think Chronos' time powers would be great. Originally, this wasn't the case, as this DC villain merely had time-themed gadgets with no temporal abilities. After years of wishing for real chronomancy, though, he ended up getting it.
After taking a deal from the demon Neron, he gained the ability to actually manipulate time. This proved to be a curse, though, as he gradually lost touch with his present and began to deteriorate. This would result in his end, but only for the original Cronos, David Clinton. Other characters would end up taking the name after his ing.
Epoch
This character from the year 3786 might seem like a job for the Justice League, given he refers to himself as "The Lord of Time." He ends up a more consistent villain of the Justice Society of America, their predecessor group. But this doesn't mean he's small potatoes, as he's one of the villains to truly understand the long game. He desires to rule the past from the future but has decided to take his time doing it.
Most of his appearances have him simply experimenting with his time powers. Moving nonlinearly and diagonally in time, he's able to access weapons and allies across millions of years. He eventually creates a location frozen in time when he waits to become "The Epoch." He figures that with enough time and meditation, he will eventually become smart enough to master all timelines.
Time Trapper
The episodic adventures of the Legion of Superheroes already takes place in the future compared to the main DC Comics universe. The team operates solely in the 30th and 31st centuries, which makes the idea of a villain coming from even further in the future strange. The Time Trapper is such a villain, coming from the very end of time itself.
The Trapper has erected an "Iron Curtain of Time," which prevents any time traveler from accessing his home time. This keeps his identity a mystery, as nobody can access his sanctuary to discover it. His identity has changed several times over the years, though, as he is still affected by changes to the time stream. It seems that the existence of a villain called Time Trapper is always constant, though.
Nimrod
Nimrod comes from the bad future of the X-Men Days of Future Past storyline. Nimrod is an evolution of the mutant-hunting Sentinels that often menace the X-Men. His name comes from the Bible, which was used there to describe a mighty hunter. It's pretty apt here, as he even pursues his prey backward in time.
Nimrod pursues the mutants back in time when they try to prevent the bad future. While he's there, he effortlessly adapts to life in the timeline. Unlike most time-traveling villains, Nimrod possesses no innate time-traveling abilities, he merely co-opts others'. His complete database and shapeshifting ability allow him to blend in and effortlessly hunt, no matter when he finds himself.
Maestro
There are a lot of variations of the Incredible Hulk, and most of them are destructive. Only a scant few of them are evil like Maestro is, though. Maestro hails from a post-apocalyptic future where he has absorbed countless amounts of radiation. This fused the Hulk and Bruce personalities, while also amplifying their worst aspects.
After an encounter with Spider-Man 2099, Maestro gains the ability to travel the time stream. He uses this to menace the Hulk of the past, eventually trying to turn Hulk into him ahead of schedule. Bruce ultimately prevails by exposing Maestro to a gamma bomb to seemingly kill him. In a great bit of time-travel-related confusion, this is the same bomb that gave Hulk his powers.
Bishop
Bishop initially debuted as a hero in X-Men comics, but as with most time-travelers, values dissonance took its toll. He hails from a future where he was a police enforcer for a future version of the X-Men. When he came into the past, he obviously aligned himself with mutants. He would soon learn that his idea of protecting mutantkind and theirs were incompatible.
Bishop’s first notable role as a villain came during the Civil War event. He ended up ing the Registration side and hunted down his former teammates. Since then, his disagreements with the X-Men have turned violent, and he became a frequent foe of the X-Force.
Reverse-Flash
Eobard Thawne was the number one fan of The Flash in the far-off future. He recreated the experiment that gave the Flash his powers and traveled back in time to meet his idol. His sanity was crushed when he learned that Barry was fated to kill him one day. He decided right then to become the Flash’s greatest enemy, and an enemy to the DC universe at large, as well.
Thawne uses time travel liberally in his quest to make The Flash’s life hell. He used it to make Flash’s childhood worse in minor ways as well as kill Barry’s mother. His time-traveling antics eventually lead him to become a multiversal threat and living paradox immune to time effects. His antics are usually centered on Barry, but countless timelines have been shattered by his schemes. The Justice League went to battle with Thawne, but only Barry can stop him.