Romance is also likely to be a prevalent theme. Writers might explore the relationship between Ichigo and Female Ukitake, how they first meet, and how their feelings develop over time. This could involve elements of forbidden love, as they may come from different backgrounds or have different responsibilities within the Bleach world.
You can try some popular fanfiction websites like Fanfiction.net or Archive of Our Own. These platforms usually have a wide range of fanfictions, and you might be able to find some related to Ichigo and Female Ukitake there. Just use the search function and type in relevant keywords.
The fanfiction can also explore the world of 'Bleach' from a different perspective through the eyes of the OC. Ukitake, being an important figure in Soul Society, can introduce the OC to the complex politics and power structures there. This can make for an exciting adventure as the OC navigates this new world while also falling in love with Ukitake.
Well, it's unique in that it takes two characters who are so different in nature. Harry is a young wizard dealing with things like the Dark Lord, while Ukitake is a more serene and spiritual character in the Bleach world. In fanfiction, this can create a contrast that authors can play with. They might explore how Harry's more action - oriented nature interacts with Ukitake's calm and philosophical approach. Also, the different magic systems of the two universes can be blended in interesting ways in this type of fanfiction.
A common theme is the exploration of their dual natures. Since Ichigo has his own powers and the female hollow ichigo has her unique hollow characteristics, fanfictions often play with how these two different yet connected aspects interact.
A common theme is the healing aspect. Given Ukitake's health issues, the OC often plays a role in either physically or emotionally healing him. Another theme is discovery, as the OC discovers the secrets of Soul Society with Ukitake as their guide.
There could be some 'Harry is Ukitake fanfiction' out there, but it may not be as common as other fanfics. One way to look for it is to use specific search terms in the search engines of fanfiction platforms. For example, you can put in 'Harry Ukitake crossover' or 'Harry and Ukitake fanfic'. Also, keep an eye on the tags on different fanfics. Sometimes, less common pairings are hidden in the depths of these platforms and can be discovered with a bit of patience and thorough searching.
I'm not sure of the exact name, but there's a fanfiction where female hollow ichigo gets separated from Ichigo during a battle. It then follows her own adventure to find her way back to him, while Ichigo is also searching for her. It's a story full of action and their unspoken bond.
One idea could be a story where Ichigo saves a female Quincy from a powerful enemy. They start off as strangers but gradually develop feelings as she recovers under his protection. They then team up to face more threats together, with their relationship growing stronger through shared battles and experiences.
One idea could be that the female Zanpakuto has a unique personality. For example, she could be sassy and constantly tease Ichigo while also being fiercely protective of him. In the fanfiction, she might have her own backstory, like being created from an ancient power that was sealed away for centuries until Ichigo awakened her.