Definitely Superboy and Captain America. Superboy with his super strength and sometimes - confused sense of self could learn a lot from Captain America's strong moral compass and leadership. Another interesting pairing would be Robin and Black Widow. Robin's detective skills combined with Black Widow's espionage expertise could make for some really cool stealth and information - gathering missions.
I think Thor and Superman would be a very interesting pairing. Thor is a god with his hammer and lightning powers, while Superman is an alien with super strength, flight, and heat vision. They could have some great battles testing their strength and then team up to take on a powerful foe like Doomsday or Ultron. Their different personalities, Thor's more brash and Superman's more moral, would also create an interesting dynamic.
One of the most interesting pairings would be Black Widow and Catwoman. They are both skilled in stealth and combat. Black Widow's training as a spy and Catwoman's thieving skills could lead to some really cool heist - like scenarios within the crossover story. And then there's Hawkeye and Green Arrow. They are both expert archers and sharpshooters. It would be great to see them compare their skills and work together in a battle situation.
Definitely Superboy from Young Justice and Black Lightning from the Outsiders. Superboy has his super - strength and Kryptonian - like abilities, while Black Lightning has his electrical powers. Their different personalities, with Superboy being more brash and Black Lightning more experienced and level - headed, could lead to some great character - development moments and interesting interactions.
Definitely the Flash and Iron Man. Tony Stark's high - tech gadgets and intelligence combined with the Flash's super - speed would make for some really cool scenes. They could work together on building some sort of super - fast vehicle or weapon. Another interesting pairing would be the Flash and Captain America. Steve Rogers' leadership and combat skills along with the Flash's speed could be a great combination for taking on enemies. The Flash could quickly get Steve into strategic positions during battles.
Inuyasha and Thor would be an interesting pairing. They both have a warrior - like nature. Thor with his hammer and Inuyasha with his sword could have some epic battles together against common enemies. They might also exchange stories about their different worlds and the powers they possess.
Definitely Captain America and Ikaris. Captain America represents the best of human values and leadership. Ikaris has his own strong sense of duty among the Eternals. They could bond over their similar leadership qualities and also learn from each other's different combat and strategic approaches. And then there's Hulk and Thena. Thena's combat skills and Hulk's brute strength could be a very volatile but also exciting combination when they face a tough enemy.
Definitely Naruto and Iron Man. Naruto is this energetic, determined ninja, and Iron Man is this brilliant, sarcastic inventor. Their personalities are so different yet they could learn a lot from each other. Iron Man could be intrigued by Naruto's chakra system and try to replicate it in some way, while Naruto would be fascinated by all of Iron Man's high - tech gadgets.
Supergirl and Black Widow would be a great pairing too. Black Widow could teach Supergirl some stealth and espionage skills, while Supergirl could show Black Widow the power of flight and super - strength. They could also bond over their experiences of being different in their respective worlds.
I think Thor and Wonder Woman would make an amazing pair. They both come from god - like lineages. Thor with his Asgardian powers and Wonder Woman with her Amazonian and divine powers could have some epic battles together against common foes. Their different yet powerful fighting styles would complement each other well.
For an Arrow - Avengers crossover fanfiction, some really interesting character pairings could emerge. For instance, Malcolm Merlyn and Loki. Malcolm is a master manipulator and Loki is the God of Mischief. They could either team up to cause chaos or be in a constant battle of wits. Also, Cisco Ramon from The Flash (since he often crosses over with Arrow) and Bruce Banner. Cisco could be fascinated by Banner's scientific knowledge and Banner could be interested in Cisco's work on the multiverse. And of course, Quentin Lance and Nick Fury. Quentin, as a police detective, and Nick Fury, as the head of S.H.I.E.L.D., could share their insights on how to keep their respective cities and the world safe.