Well, one possible plot could be that Naruto accidentally travels back in time and meets his mother. His mother, Kushina, might initially be shocked but then quickly recognize him as her son. She could then start to teach Naruto some of the Uzumaki clan's secret techniques that she never got the chance to pass on in the original story.
Another character could be the Nine - Tailed Fox. Kushina was once the jinchuriki of the Nine - Tailed Fox. When Naruto meets his mother, the topic of the Nine - Tailed Fox might come up. Maybe Kushina could tell Naruto some secrets about controlling the Nine - Tailed Fox's power that she learned during her time as its jinchuriki.
In 'Naruto meets his mother' fanfictions, a prevalent theme is the filling of a void. Naruto has always felt the absence of his parents, and this meeting fills that emotional gap. Additionally, there might be a theme of growth. His mother's presence could inspire Naruto to grow even more as a ninja and as a person. And sometimes, the theme of redemption can be there, especially if there are elements in the story related to Naruto's past struggles and how his mother's appearance helps him move forward from them.
In such a fanfiction, Naruto might have an emotional moment. He could finally learn more about his family's past directly from his mother. Maybe she would share some secret jutsu or wisdom with him.
In the 'naruto meets his brother fanfic', it's possible that the brother has a different view of the ninja world compared to Naruto. This could lead to some interesting debates between them. The brother might be more cynical or have a darker past that Naruto has to come to terms with. There could also be a rivalry at first, but as they get to know each other better, they form a strong bond. Maybe the brother has some special abilities that Naruto has never seen before, and Naruto is eager to master those abilities as well.
In such a fanfic, Naruto might initially be confused when he meets his counterpart. They could compare their lives, skills, and experiences. Maybe they would have a friendly spar to test each other's strength.
In such a fanfic, Naruto might finally get to understand his family heritage better. His dad could teach him some new jutsu that only the Uzumaki family knows.
One possible scenario could be that Blu is initially nervous when he meets his mother. He might be hesitant, but as they start to interact, he realizes how much he has in common with her. For example, they could both have a unique way of communicating with other birds. Their reunion could be filled with a mix of emotions, from joy to a bit of awkwardness at first.
His brother could be an unknown Uzumaki. Since Naruto is from the Uzumaki clan, it would make sense for his brother to be from the same clan. Maybe he was hidden away for some reason, like to protect him from the same threats that Naruto faced as a child.
Goku's reaction could be a mix of shock and happiness. On one hand, he never expected to actually meet his parents. On the other hand, he has always longed for a family connection. He might start asking them a million questions right away about their lives, Saiyan culture, and what it was like when he was born.