Sakura Haruno might enter the MHA universe through some sort of multiverse portal. Once there, her strong - willed and determined nature would make her a great hero - in - training. She could learn to use her physical strength, which she had developed in the Naruto world, in combination with a new MHA - style quirk. For example, she could have a quirk that enhances her strength even further when she focuses her chakra (or a similar energy concept in MHA). This would make her a formidable force against villains.
Batman in the My Hero Academia world would likely be a bit of an outsider at first. His dark and brooding nature might contrast with the more colorful and often optimistic characters in MHA. However, his intelligence would be highly respected. He could use his detective skills to help solve some of the mysteries that pop up in the MHA world, like the origin of certain quirks or the identity of villains who are hiding in plain sight. And his martial arts expertise would make him a formidable opponent in battles against villains.
Well, Goku's super strength and his ability to constantly power up could be a huge asset in the My Hero Academia fanfiction world. He could be like an otherworldly hero with his Saiyan powers. His Kamehameha wave would be an extremely powerful quirk - like ability. Maybe he could be a visiting hero from another dimension, coming to help out in the battles against the villains in the My Hero Academia universe.
Well, one way could be that Ichigo arrives in the My Hero Academia world through some sort of interdimensional portal. His powers, like his Soul Reaper abilities, would be seen as a very unique and powerful quirk. He might end up at UA, either as a student or a guest instructor. His strong sense of justice would align well with the values of the heroes in that world.
In fanfiction, Broly might be a villain who comes to the My Hero Academia world seeking a worthy opponent. His raw power would pose a huge threat to the heroes, and they'd have to figure out how to stop him without getting killed.
In a fanfiction scenario, the Hulk might be a result of a secret experiment by the League of Villains to create an ultimate weapon. But instead of being fully controllable, he breaks free and becomes a wild card in the power dynamics of the My Hero Academia world. His presence would disrupt the existing balance between heroes and villains as everyone tries to either control or destroy him.
Well, one way could be that his alchemy skills are seen as a unique quirk. He might attend UA and struggle to adapt to a world where heroics are more about using superpowers rather than alchemy. For example, he could have a hard time during combat training because his methods are so different from the typical quirk - based attacks.
Deadpool would be a wild card. His regenerative abilities would make him seem like he has a quirk similar to Recovery Girl's but on steroids. He'd likely not follow the normal hero - society rules. For instance, he might start fighting villains in the middle of a civilian - filled street just because he felt like it. His presence would also disrupt the power balance as he has a vast array of weapons and combat skills that are not typical in the My Hero Academia world.
She could be a transfer student from another hero academy with her own set of unique skills. Her powers would likely make her stand out among the MHA students.
One way it could fit is by having a character with a quirk that allows them to mimic the Sharingan's abilities. For example, they might be able to copy other heroes' or villains' quirks in a similar way to how the Sharingan can copy jutsu in Naruto. This would add a whole new level of strategy and intrigue to the My Hero Academia world.
Perhaps a 'Healing Aura' quirk. Given Sakura's medical skills in Naruto, in the MHA fanfiction, she could have a quirk that emits a healing aura. This aura could not only heal physical wounds but also have an effect on quirks that have been damaged or overused. It would make her a valuable asset in battles and in hero agencies, as she could both fight and heal her comrades.