There are indeed such fanfictions. In these stories, Rin's survival can have a huge impact on the other characters. For example, it could change Obito's path completely. Instead of becoming consumed by hatred, he might have a different future with Rin alive. Also, Kakashi's character development could take a different turn as well, since Rin was an important part of his past.
One interesting fanfiction could be where Rin becomes a powerful medical ninja and uses her skills to prevent many deaths in the village. Another might be where she teams up with Kakashi and Obito to face new threats that the original series didn't cover.
One possible plotline could be Kushina teaching Naruto about the Uzumaki clan's secrets. Since she was an Uzumaki, she could pass on unique jutsu and knowledge that no one else in the village might know. For example, she could teach him advanced sealing techniques. Another plotline could be Kushina's influence on Naruto's relationship with the other villagers. Her presence might have changed how some of the villagers who were once cold to Naruto would now interact with him. Also, Kushina could be involved in the political affairs of the village, using her wisdom and strength to help Konoha face external threats more effectively.
Naruto would likely be more confident earlier. With his mother around, he'd have someone who unconditionally loves and supports him from the start. He wouldn't have to seek as much approval from others. His growth might also be more focused on learning Uzumaki techniques rather than just trying to prove himself. He could be more stable emotionally as Kushina could help him deal with his inner turmoil, like the Nine - Tails situation.
One idea could be that Rin, with her medical skills, tries to save Kakashi but fails due to some unforeseen circumstances. Maybe an enemy uses a powerful jutsu that she can't counter in time. This would be a tragic twist, as her being alive doesn't change the outcome for Kakashi.
In a fanfiction where Naruto's parents are alive, they could play a major role in changing the politics of the Hidden Leaf. Minato, being a former Hokage, and Kushina with her strong Uzumaki blood, might work together to strengthen the village's defenses and relations with other villages. This would also mean Naruto doesn't have to struggle alone and could learn advanced techniques much earlier from his parents.
A possible plot could be that Kakashi sacrifices himself to save Rin from a powerful enemy. This would be ironic as usually, Kakashi is the one protecting others. With Kakashi gone, Rin might then discover some secrets that Kakashi was keeping from her. These secrets could change her view of him and also drive the rest of the fanfiction as she tries to come to terms with his death and the new information.
Another option is Wattpad. While it has a wide variety of content, you can still find some interesting 'naruto rin fanfiction' there. Just be aware that the quality might vary, but it's definitely worth a look if you're really into this kind of fan - made stories.
Yes, in some Avengers fanfictions, authors like to create alternate universes or timelines where Howard and Maria are still alive. This can lead to very interesting plot developments, such as Howard contributing his scientific genius in new ways and Maria being involved in the Avengers' world more directly.
It's because fans have a strong passion for the original story and want to explore different scenarios and character developments.
In many Avengers fanfictions, their fate varies. Some writers keep them alive to explore new plotlines, while others might use their supposed deaths to drive the story in a different direction.