One idea could be that Sasuke somehow ends up in the Bleach universe and teams up with Ichigo. They could face off against a common enemy that has powers related to both the Sharingan and the Zanpakuto. For example, a villain who can manipulate souls like in Bleach but also has the ability to copy techniques like the Sharingan.
Sasuke's Sharingan could potentially be used to analyze the reiatsu patterns in the Bleach universe. This would allow him to predict the movements of his opponents, much like he does in the Naruto world. For example, if he was facing a Soul Reaper or a Hollow, he could see the flow of their reiatsu and anticipate their attacks.
Well, Naruto's chakra could be translated into a form of spiritual energy in the Bleach universe. His ability to create shadow clones might be similar to some low - level Hollow cloning abilities. As for Sasuke, his Sharingan could be a unique type of spiritual vision. Maybe it could detect hidden spiritual pressures or weaknesses in enemies. They would have to adapt to the different power systems in Bleach, like learning about Zanpakuto and the various forms of Hollowfication and Soul Reaper powers.
Naruto would probably befriend Ichigo right away. They both have a strong sense of justice and a desire to protect their friends. Sasuke, on the other hand, might be more aloof at first. He could be intrigued by Urahara Kisuke's mysterious nature. Naruto would likely get along well with Orihime too, as she has a kind heart. Sasuke might have a more competitive relationship with Byakuya, seeing his power and discipline.
One idea could be that Ichigo Kurosaki from Bleach somehow gets transported to the Victorian era world of Black Butler. He could be mistaken for a demon or some kind of otherworldly being. Sebastian, being the ever - curious demon, might be intrigued by Ichigo's powers and his strong sense of justice. Another idea is that Ciel Phantomhive has to deal with Hollows suddenly appearing in his world. He enlists the help of the Soul Reapers from Bleach to combat this new threat. They could form an uneasy alliance where the Soul Reapers are not used to the complex politics of the Black Butler world, and Ciel has to figure out how to work with these super - powered beings.
I really like 'The Shinigami and the Ninja'. It's a well - written fanfic where the author does a great job of integrating the different mythologies and power systems. You get to see Bleach characters like Rukia in the Naruto world, dealing with things like chakra and ninja villages. It adds a fresh twist to both universes.
One characteristic is the exploration of new settings. Since it's a crossover, Toshiro is often placed in different fictional worlds or situations not in the original Bleach story. For example, he might end up in a steampunk world or a world with magic systems different from Soul Society's.
One interesting idea could be that characters from Bleach are somehow transported to the Naruto world during the Chunin Exams. For example, Ichigo could end up participating in the exams. He might use his Soul Reaper powers in the forest of death, which would give him an edge against the ninja there. His Zanpakuto skills could be misinterpreted as some kind of advanced ninja tool or jutsu.
A good 'Bleach' crossover fanfiction often has well - integrated universes. For example, if it's a 'Bleach' and 'Dragon Ball' crossover, the power levels and the different types of energy in both worlds should be combined in a believable way. If the fanfic just throws the characters together without any thought to how their worlds' rules work, it won't be as good.
One great Hinata crossover with Bleach fanfiction is 'Hinata in the World of Bleach'. It shows Hinata from Naruto ending up in the Bleach universe. She brings her unique skills and gentle nature to the story. It's interesting to see how she interacts with the characters in Bleach like Ichigo and Rukia.