The best way to know where to start is to look for discussions on manga-focused websites. Fans often share their experiences and advice on continuing after the anime. Another option is to check social media groups dedicated to Baki Hanma to get suggestions from fellow fans.
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.
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.
One great story could be where the OC is a strong - willed martial artist who challenges Yujiro Hanma. Their interactions are filled with intense battles and mutual respect that gradually turns into a complex relationship.