One idea could be a story where Itachi and Kushina meet in a parallel universe. In this universe, the events of the original Naruto storyline are altered, and they end up on the same side, fighting against a new common enemy. Their unique abilities, Itachi's Sharingan and Kushina's powerful chakra, would make for an interesting combination in battles.
Let's imagine Itachi Uchiha in love with a fellow Uchiha. They grew up together, trained together. Their love was based on a deep understanding of each other's pain and power. But when the Uchiha clan's fate was at stake, Itachi had to make difficult choices. His love for her was strong, but his loyalty to the village made him do things that seemed to shatter their relationship. In the end, his love remained in his heart, a hidden and painful memory.
Itachi Uchiha's full story is one of great sacrifice and hidden motives. As a member of the Uchiha clan, he was aware of the growing unrest within the clan against the Hidden Leaf. Instead of allowing a full - blown civil war, he made the difficult choice to kill his clan mates. His actions were misjudged by many, especially Sasuke. Itachi's time in the Akatsuki was also full of intrigue. He constantly had to balance his true loyalty to the Leaf with his role in the criminal organization. And all along, his love for Sasuke was his driving force, even if it seemed like he was cruel to him at times. He wanted Sasuke to become strong enough to take revenge on him and in doing so, free himself from the cycle of hatred.
Another good one is 'Itachi Meets the Avengers'. Here, Itachi's calm and strategic mind makes for some amazing interactions with the Avengers. His abilities seem out of this world to the heroes at first, but they soon realize how useful he can be in battles against powerful foes like Thanos.
Another concept could be a story where the magic in the Harry Potter world and Itachi's ninjutsu are somehow combined. Imagine Itachi using his fire - style jutsu along with a spell from the Harry Potter world to create a unique and powerful attack. This could be used against a common enemy that threatens both the ninja world and the wizarding world.
One common theme is the exploration of gender - role reversal. Since Itachi is male in the original, seeing how a female version would handle the same situations adds a new dimension. Another theme is relationships. Female Itachi's relationships with family, especially Sasuke, can be different. For example, it might be more nurturing in some fanfictions. Also, the theme of power and how a female Itachi would use and develop her powers is often explored.
Another great Itachi Uchiha crossover fanfic idea is him crossing into the Lord of the Rings universe. He would be a formidable fighter against the orcs and other dark forces. His intelligence and strategic mind could help in the battles against Sauron's armies.
There's also 'The OC's Journey with Itachi'. This fanfiction focuses on how the OC's presence changes Itachi's perspective on certain things. The writing style is captivating, and the author does an amazing job of creating a believable relationship between Itachi and the OC. It has some really heart - warming moments.
In many fanfictions, the scenario of Naruto and Itachi killing the Uchiha clan is a very interesting but also controversial topic. One aspect could be the change in Naruto's character. Usually, Naruto stands for justice and protecting others. If he were involved in such a massacre, it would be a huge deviation from his original character. Maybe in the fanfiction, there could be some extreme situations that force him to do so, like being mind - controlled or having some false information.