When it comes to the more complex plot points, the interaction between Ichigo's Hollow side and the Dark Magic in the Harry Potter universe is very engaging. For example, if his Hollow side was somehow influenced by the Dark Arts or if it could be used to fight against it in a unique way. This could lead to a whole new set of challenges and character development for Ichigo within the wizarding world.
One interesting plot point is when Kagome's spiritual powers interact with magic in the wizarding world. For example, her ability to sense and purify evil could be used to detect dark magic in Hogwarts. Another is how she might introduce new concepts of magic from her own world to the wizards.
One idea could be that the OC has a special power that only activates when in close proximity to Ichigo. For example, the OC can sense Hollows from a great distance, which helps Ichigo in his battles against them.
Well, one interesting plot point is when the magic and alchemy clash. For example, in some fanfics, a wizard tries to use alchemical techniques and it backfires because the two systems are not fully compatible at first. It creates a lot of chaos and makes for an exciting read.
A common interesting plot point is the culture shock. Danny, coming from a world where ghosts are more of a local, small - town kind of threat, suddenly being in a world full of magic like Harry Potter's. He has to learn about things like Quidditch and the different houses in Hogwarts. It's like a fish out of water story, but with a supernatural twist.
Well, one interesting plot point is the clash of two different worlds. The magical world of Harry Potter and the high - tech superhero world of Peter Parker. For example, in some fics, they have to figure out how to use magic in a world full of advanced technology or vice versa.
One interesting plot point is the power struggle. When Harry Potter's magic meets the power system of the Shield Hero, there's often a conflict about who is more powerful or how they can combine their powers. For example, the Shield Hero's ability to level up his shield might be pitted against Harry's spellcasting abilities.
One interesting plot point is the combination of magic and survival skills. For example, in some fanfics, wizards have to use spells to hunt or defend themselves in the Hunger Games - like setting. Another is the clash of cultures from the two worlds. Hogwarts students with their magical upbringing facing the brutal and more practical world of the Hunger Games.
I'm not sure of a specific title off - hand, but you can often find some really cool ones on fanfiction.net. Look for ones with high ratings and lots of reviews. Usually, the ones that combine Ichigo's sword - fighting skills with Harry's magic in creative ways are the most engaging.
The cultural differences between the two worlds also make for great plot points. In Superman's world, it's more about modern society and heroics in a big city. In Harry Potter's world, it's a hidden magical society. Fanfics often explore how characters from one world react to the other world's culture. Like Superman being amazed by the magical creatures in Hogwarts. And it can be really engaging to read about how they bridge these cultural gaps.
One interesting story could be where Ichigo and Yachiru go on an adventure in the Soul Society together. They might encounter some strange spirits and have to use their combined skills to defeat them. Ichigo's determination and Yachiru's energetic nature would make for a great dynamic during the adventure.