Erik Killmonger, aka N'Jadaka, is a frequent and deadly opponent of the Black Panther. Killmonger has attempted to seize the throne of Wakanda on several occasions, seeking to turn it into the seat of a global empire. He has been killed and resurrected many times, and each return finds N'Jadaka more powerful and deadly than the last.
Much of Killmonger's rage comes from the way that Wakanda has sat idly by while the rest of Africa is pillaged and exploited. His goal comes from a warped sense of justice brought about by violent retribution, and he would likely find allies in the DC Universe rogues' gallery who would sympathize--and others that would hate him.
10 KILLMONGER TEAM-UP: Ocean Master
Erik Killmonger would certainly find a kindred spirit in Orm Marius, aka the Ocean Master. Both feel that they have been denied a throne, and both want to use that throne to wreak horrible vengeance on the rest of the world for past crimes--Ocean Master resents the surface world for polluting and raiding the oceans. Killmonger would likely agree to help Ocean Master take the throne of Atlantis in exchange for help in taking Wakanda from Black Panther.
9 KILLMONGER WOULD HATE: Lex Luthor
Lex Luthor is a billionaire who feels that he is owed the world for his money and brilliance. Killmonger would almost certainly resent this, and he likely feels the same way about Iron Man. Killmonger probably wouldn't go out of his way to overthrow Luthor, but he would probably be among N'Jadaka's first targets once he took the throne of Wakanda.
8 KILLMONGER TEAM-UP: Black Manta
Erik Killmonger's relationship with Black Manta would likely be similar to his partnership with Ocean Master. Black Manta and Erik Killmonger both have grudges against monarchs of hyper-advanced societies.
Erik Killmonger and Black Manta would form a pact to help one another kill Black Panther and Aquaman.
7 KILLMONGER WOULD HATE: The Penguin
The Penguin is a child of fortune with a deep sense of entitlement. His entire criminal enterprise is built upon his feeling that he is owed a large stake in Gotham City as a Cobblepot. He didn't start from nothing, and he is now a fat little man with a ton of money that keeps him from facing the full consequences of his actions. N'Jadaka would hate this.
6 KILLMONGER TEAM-UP: Black Adam
Black Adam feels a profound sense of pride and nationalism for his homeland of Kahndaq. He doesn't have an imperialist mindset like Killmonger, but he will do anything to protect his homeland. Killmonger would certainly respect this. Given the extent of Black Adam's powers, it's unlikely that he would find much to offer in Killmonger, but one could easily imagine the two forming a friendship and mutual respect.
5 KILLMONGER WOULD HATE: Captain Nazi
Captain Nazi is a Shazam villain with a power set similar to Shazam himself. He was a super-soldier that fought on behalf of Nazi Germany during World War II, and he was resurrected in the modern era by Wolf Krieger and Madame Libertine. He is a Nazi, as his name suggests, and believes everything that entails. Needless to say, he would hate Killmonger, and Killmonger would hate him.
4 KILLMONGER TEAM-UP: Cheetah
Barbara Minerva is cursed to live in her feline form by the gods and has been forsaken by wider society. While Killmonger doesn't have an identical struggle, one could easily imagine that N'Jadaka would feel some sympathy for the Cheetah.
That said, Cheetah has a grudge against the Amazons and Themyscira, and Killmonger could leverage aid in Cheetah's crusade against the Wonder Woman and the Amazons for help against Black Panther and Wakanda.
3 KILLMONGER WOULD HATE: Red Lion
Red Lion is a character created by Christopher Priest, who wrote Marvel Knights Black Panther for Marvel, during his run on Deathstroke. He is a parody of the Black Panther as a brutal African warlord. Red Lion is a warlord in red feline armor who uses his position and equipment to use and abuse power. Killmonger would see the Red Lion as a cruel monster who abuses his own people for no other reason than greed and sadism. In a way, Red Lion is how Kilmonger already sees the Black Panther, and he would enjoy killing the Red Lion.
2 KILLMONGER TEAM-UP: The Joker
Killmonger is not a nihilist, but the Joker is an agent of chaos who helps destabilize a major American city while battling the Batman. Killmonger could easily talk himself into helping the Joker escalate his murderous schemes in the United States and help foment chaos and anarchy. If the Joker, as he so often does, tried to turn and kill N'Jadaka, he would find Killmonger hard to kill.
1 KILLMONGER WOULD HATE: Deathstroke
Killmonger has done some work as a mercenary, but he would find Deathstroke the Terminator a distasteful figure. Slade is a successful and rich man thanks to his mercenary work, and he only does it for the glory and legacy he can build as the world's most sought-after mercenary. He has no higher calling for himself, even if he does have a moral code. Killmonger would find this level of self-reverence grotesque and would hate Deathstroke.