A possible plotline is that Kushina is the center of a prophecy and Naruto is fated to be part of her harem. This could bring in elements of different clans trying to influence the situation. Maybe the Uchiha clan wants to use Naruto's relationship with Kushina to their advantage, while the Hyuga clan also has their own motives. Naruto then has to deal with the politics of the ninja world while also handling his feelings for Kushina and the other characters in the harem - all of which can make for a really engaging fanfiction.
One interesting plotline could be Naruto being transported back in time to when Kushina was young and him having to navigate a harem situation while also trying to change the future for the better. Another could be an alternate universe where Kushina is in a position of power and Naruto has to win her over among a group of suitors in a harem-like setting.
Well, in some naruto x kushina harem fanfictions, there might be a plot where Naruto discovers a hidden power within himself that is linked to Kushina and this attracts a harem of characters. For example, some shinobi might see this new power as a sign of great potential and they become part of Naruto's 'harem' in a way, all while his connection to Kushina deepens. It could lead to adventures where they all have to work together and Naruto has to balance his relationships.
One possible plotline could be an alternate universe where Futa Kushina has unique ninja abilities that she uses to protect Naruto in a different way than in the original story. Maybe she has some special time - space jutsu that allows her to foresee and prevent certain threats to Naruto.
Another plotline could involve the challenges they face from the village. People might have different opinions about the union, some seeing it as a strategic move while others might be jealous or against it for various reasons. They would have to deal with the gossip and political implications within Konoha.
One interesting plotline could be Naruto going on a mission to Kumogakure and getting involved with multiple Kumo ninjas in a friendly way that gradually turns into a harem situation. For example, he might help them with a local threat and in the process, they all develop feelings for him.
Another plotline might involve Kushina being brought back to life and getting to know Naruto as a young man. As she spends time with him, she discovers his determination and the way he has grown despite his hardships, which makes her develop feelings for him. For example, she could see how he interacts with his friends and how he's always there to protect them, and that could draw her to him.
One possible plotline could be Naruto exploring his mother's past in more detail. Maybe he discovers some hidden jutsu or secrets that Kushina left behind. Another could be his relationship with his parents in a more in - depth way, like how they would have raised him if they were alive.
One possible plotline could be Naruto and Kushina teaming up to face an extremely powerful enemy that no one else in the village can handle. Their godlike powers would be put to the test in protecting Konoha.
One interesting plot could be Naruto being transported to an alternate dimension where Kushina is part of a harem. He has to navigate the complex relationships within the harem while also dealing with new threats in this dimension. Another plot might involve Kushina having to choose between different suitors in the harem setting, all while Naruto is trying to protect her and the village.
One possible plotline could be Naruto finding himself in the Family Guy universe and being pursued by some of the female characters there, creating a comical and chaotic harem situation. For example, Lois might be intrigued by Naruto's ninja skills and his different worldliness, leading to some humorous interactions.
One possible plotline could be that Naruto is influenced by some dark force and turns 'evil'. Kushina, having come back to life somehow, tries to understand what has happened to her son. She then embarks on a journey to find a way to reverse the effects, leading to a series of adventures where they interact in different ways, like Kushina trying to jog Naruto's memories of their family bond.
One interesting plotline could be Kushina's influence on Naruto's chakra control. Since she was a jinchuriki too, fanfics might explore how she could have taught Naruto some unique techniques related to the Nine - Tails' chakra if she had been alive longer.