Saphira, Eragon's dragon, and Gwaihir, the great eagle in Lord of the Rings. These two powerful flying creatures could form an alliance. They could communicate in their own ways and work together to provide aerial support during battles, as well as help in transporting important characters across great distances in Middle - earth and Eragon's world.
I think Frodo and Lucy would make an interesting pairing. Frodo is burdened with the One Ring and has seen a lot of darkness, while Lucy is full of innocence and hope. Their interactions could show how the two different worlds' outlooks can influence each other. For example, Lucy's unwavering faith might give Frodo some new strength in his fight against the Ring's power.
Naruto himself would be really interesting. His boisterous personality and never - give - up attitude would be a contrast to the more solemn characters in 'Lord of the Rings'. He could bring a new energy to the story, and his unique jutsu would make him a force to be reckoned with in Middle - earth.
I think Legolas could be really interesting. In 'The Hobbit', there are no elves from Mirkwood really involved in the story in the way Legolas is in 'The Lord of the Rings'. So, if you cross over the two, you could explore how Legolas might interact with the dwarves in a different context, considering the historical tension between elves and dwarves. He could also use his skills as an archer in new and unexpected ways, perhaps influenced by the events in 'The Hobbit' that he hears about from Gandalf or other characters.
Another great crossover could be between Gandalf and Urahara. Gandalf is a wise and powerful wizard, and Urahara is a very intelligent and somewhat mysterious character in Bleach. They could share their knowledge of magic and strategy. Gandalf might be intrigued by Urahara's unique inventions and scientific approach to spiritual matters, while Urahara could learn from Gandalf's vast experience and wisdom in dealing with different races and powers.
One possible plot could be that Eragon somehow gets transported to Middle - earth. He could meet Aragorn and learn from his leadership skills. Maybe they would join forces to fight a common enemy like a new breed of dark creatures created by a combination of Sauron's magic and the dark forces from Eragon's world.
Yukari (from Persona 3) and Chie (from Persona 4). Yukari is very outspoken and has a bit of a sarcastic side, while Chie is energetic and a bit of a tomboy. Their different personalities could lead to some really fun and comical interactions, especially when they're facing Shadows together or just hanging out in the school setting.
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.
Another great pairing could be Sasuke and Griffith. They both have a certain level of ambition and a thirst for power. They might start off as rivals, constantly trying to one - up each other in terms of strength and influence. But as they face greater threats together, they could learn to respect each other and even form an uneasy alliance. It would be fascinating to see how their different motives play out when they are forced to work together.
I think Spyro and Kakashi would be an interesting pair. Kakashi is a very experienced and intelligent ninja, and Spyro is a powerful dragon with unique abilities. Kakashi could be intrigued by Spyro's magic and his different combat style. And Spyro could be in awe of Kakashi's Sharingan and his vast knowledge of ninjutsu. Also, Spyro and Sakura could be a good pair. Sakura has grown into a strong kunoichi, and Spyro could help her further develop her combat skills, especially in terms of using her strength in more creative ways.