Thor has fought most of Marvel's greatest villains in the comics and the MCU, but he has a large and dangerous group of villains all his own. Most of them have made it to the screen in recent years, though some remain on the sidelines. Thor: Love And Thunder will likely change that for some of them, and certainly will for Gorr the God Butcher, one of Thor's most powerful villains in the movies or the comics.
Thor has faced off against some of the greatest cosmic and mystical threats in the Marvel Universe, including members of his own family. Loki might be his greatest villain in the movies and the comics, but the God of Mischief isn't necessarily the most powerful. Far more dangerous villains have confronted Thor, as Loki found out the hard way in the MCU in Avengers: Infinity War.
Ulik
Ulik is one of the few villains from Marvel Comics who can take Thor in a fight. He possesses incredible superhuman strength as a Rock Troll, able to wound Thor and even make him bleed in some instances. He's also incredibly durable himself.
Ulik can also fly thanks to his Codgel, a mace-like weapon that's as mystical as Mjolnir. Ulik features in some of the best Thor comics to read before Love And Thunder, but he's yet to appear in the MCU.
Hercules
Hercules is one of Thor's most powerful villains in the comics and is likely going to be in the MCU shortly. Hercules possesses the god-like strength of the mythological figure, and he is virtually unlimited in his power.
He's not without his limitations though. He can be easily thrown into a rage. leaving him wild and easy to exploit. Hercules will likely appear in the new movie, given that the trailer seems to hint at his father, Zeus, appearing in Olympus.
Seth
Seth is one of the most powerful members of the Heliopolis gods of ancient Egypt and fought Thor in his first appearance in Marvel Comics. Seth is incredibly strong, though not as strong as Ulik, possessing superhuman speed and stamina.
What sets Seth apart is his immortality. Like the majority of the Ennead from the comics, Seth is invulnerable to most forms of attack, including most mystical forms, and is also able to shapeshift, transforming into a gigantic serpent. He has yet to appear in the MCU but is likely to appear soon, as most of the Ennead has appeared in Moon Knight.
Enchantress
The Enchantress is one of the most powerful Thor villains in the comics and one of the most powerful sorcerers. She can cast powerful spells that confuse and enthrall people, as she did to Thor early in their encounters in the Marvel Universe.
As an Asgardian, the Enchantress has superhuman strength, speed, and stamina. Amora, the classic Enchantress from Marvel Comics, has yet to appear in the MCU, though a version of her has appeared in the form of Sylvie, who is based on the Sylvie Lushton version.
Loki
Loki is one of the most powerful magic users in Marvel Comics and the MCU. He can cast illusions, which he uses predominantly to hide his Frost Giant appearance and conjure mystical energy blasts and shields.
Loki is one of the principal villains of the MCU and though his primary version has died, a variant continues in the multiverse and is likely to continue to play a role in the MCU, possibly even a significant one as Kang The Conqueror becomes more of a threat.
Midgard Serpent
The Midgard Serpent, or Jormungand, is one of the most powerful Thor villains in the comics. Jormungand is immortal and essentially invulnerable, though Thor could injure him, His venom was lethal to Asgardians, making him especially dangerous. He could also cast spells and illusions, disguising his appearance and size.
He appears in the iconic run by writer and artist Walt Simonson, responsible for some of the best Thor comics of the 80s. He hasn't appeared in the MCU yet, though he could appear in the upcoming movie given all the wild creatures featured in the trailer.
Hela
Hela is the queen of Hel and one of the most powerful Thor villains in the comics and the MCU. She has control over life and death and can resurrect the dead. She also can control where the spirits of Asgardians go after they have died.
She is immortal and possesses Asgardian strength and endurance. She wields the Nightsword, a powerful weapon that became unlimited black daggers in the MCU and may be connected to the Necrosword, the weapon of Gorr the God Butcher.
Surtur
Surtur is a Fire Giant and one of the most powerful beings in the Nine Realms. An immortal being with virtually unlimited strength and command over flame and fire, he is responsible for the destruction of the realm of Asgard in the MCU.
Surtur was able to accomplish this with the Twilight Sword, a massive mystical weapon that can cut through dimensions and reality. It is essentially limitless in its power and could play a role in the future of the MCU given where the upcoming movie is going.
Gorr The God Butcher
Gorr The God Butcher will be the main villain of Thor: Love And Thunder and he's one of the most powerful villains in the comics. While he doesn't have any superpowers of his own, he's armed with Necrosword, a weapon that makes him a god killer.
The Necrosword is capable of slaying gods of any power and Gorr used it to behead a Celestial, one of the most powerful cosmic beings in the Marvel Universe. With the sword, Gorr the God Butcher is essentially a god himself.
Thanos
The Necrosword can kill gods, but it can't wipe out half of all life in the cosmos in a single stroke. Armed with the Infinity Gauntlet, Thanos ranks among the most powerful villains Thor has ever faced in the comics or the MCU. On both occasions, he initially loses.
Thanos can manipulate matter and energy on a cosmic scale, as well as reality. He is strong enough to fight Thor and all of the Avengers single-handedly, with his cosmic power supplemented by his superhuman Titan physiology.