I think Iron Man and Tyrion Lannister would be a really interesting pairing. Iron Man is this brash, genius billionaire, and Tyrion is the clever, outcast dwarf in Westeros. They could bounce ideas off each other, with Iron Man showing Tyrion his high - tech gadgets and Tyrion teaching Iron Man about the political games in Westeros.
Black Widow. She's a master spy and assassin. In the world of Game of Thrones, she could easily blend in with the various spies and informants. She could play the game of thrones better than most of the characters there, using her charm and combat skills to manipulate the situation to her advantage. She might even be able to uncover some of the deepest secrets of the Seven Kingdoms.
Another interesting pairing would be AOC and Arya Stark. Arya is a fierce and independent fighter. AOC could inspire Arya to think about the bigger picture in terms of changing the social order. Meanwhile, Arya could protect AOC from the many enemies she would surely make in the cut - throat world of Game of Thrones as she tries to implement her ideas.
I think Jon Snow and Spock would make an interesting pair. Jon is a natural leader, and Spock's logical thinking could complement his more instinct - based leadership. They could learn a lot from each other, with Jon showing Spock about the harsh realities of a feudal society and Spock teaching Jon about the power of reason.
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.