He could team up with Luffy. Luffy is always open to new allies, and Broly's power would be a great addition to the Straw Hat crew. They could go on adventures together and face powerful enemies.
Goku could be a likely ally. Despite their initial conflicts, Goku has a way of seeing the good in people. He might approach Broly and convince him that they can work together to win the Tournament of Power for their universe. Their combined strength would be a formidable force.
In a crossover with One Piece, Luffy could be an ally. Luffy is known for his open - mindedness and ability to befriend almost anyone. He would see Broly's power and might try to get him to join his crew or at least fight alongside him against common enemies. They could have some really fun interactions, like Luffy trying to make Broly laugh or share his love for food with him.
Issei could be one of Broly's potential friends. Issei is known for his friendly and outgoing nature. He might be intrigued by Broly's power and want to befriend him. Also, Asia could be a friend. She has a kind heart and might reach out to Broly, who could be seen as an outcast due to his strength and different background. Her kindness could break through to Broly.
In a crossover with the Naruto universe, Naruto himself could be an ally. Naruto has a way of seeing the good in people, and he might try to reach out to Broly and convince him to use his power for good. His ability to befriend and understand others could be key.
Yes, there are likely fanfictions out there with the concept of 'naruto is broly'. Fanfiction writers often come up with creative crossovers like this. You can try searching on popular fanfiction websites such as FanFiction.net or Archive of Our Own.