Well, in these fanfictions, a key element is the evolution of their skills. Sasuke might learn new techniques to better protect Naruto, and Sakura might enhance her medical ninjutsu for emergency healings. The setting also matters. It could be set during a new war or in a time of peace where they still need to be vigilant. And of course, the way they interact with Naruto, like Naruto's reaction to being protected by them, which can range from being grateful to feeling a bit guilty for putting them in danger.
One interesting plot point is when they have to face an enemy who can manipulate time. Sakura and Sasuke have to work against the odds to keep Naruto safe. Sakura uses her chakra control to try and disrupt the time - manipulation, while Sasuke uses his Rinnegan (if he has it in the fanfic) to counter the enemy's attacks directly related to Naruto.
Well, in these fanfictions, the setting is important. Since it's for their birthdays, it could be a beautifully decorated place like a garden full of cherry blossoms for Sakura or a more private, serene location for Sasuke. Their character traits play a big role too. Sasuke might show a softer side on his birthday, and Sakura's determination to make the day great for him would be highlighted. And of course, there could be some cute moments like Sakura baking a special cake for Sasuke, which shows her love and care in a very domestic way.
The family and friends' reactions play a significant role. In many fanfictions, characters like Kakashi, Sasuke, and Ino have different reactions to Sakura's desire to marry Naruto. Sasuke might be a bit jealous or at least have mixed feelings. Kakashi, on the other hand, could be supportive and offer some wise advice. Also, the cultural and village - related aspects are often explored. How the Hidden Leaf Village would view their union and what it means for the future of the village in the context of the fanfiction.
The exploration of their pasts is an important element. Fanfictions might delve deeper into what it could have been like if they had recognized their brotherly bond from the start. There could be flashbacks showing how they protected each other as children, which was not as prominent in the original. Their future together is also a key aspect. They could be seen as the future leaders of the village, with their bond being the foundation for a new era of peace and prosperity. Their bond could also lead to new ninja techniques being created as they combine their unique abilities.
There's a fanfiction called 'Sakura's Redemption'. In it, Sakura has to make up for some past mistakes she made in relation to Sasuke and Naruto. It's unique because it gives her a chance to really shine and show her growth as a character. It's not just about the boys all the time.
One common theme is friendship. Their relationships with each other are often explored, showing how they grow closer and support one another. Another theme is growth. Fanfictions usually depict how they become stronger as ninjas over time. For example, Naruto might master a new jutsu, Sasuke might gain more control over his powers, and Sakura might improve her medical skills.
One interesting fanfiction could be where they go on a joint mission that tests their friendship and teamwork in ways they haven't experienced before. For example, they might have to face a new type of enemy that requires all of their skills combined. Another could be a story set in an alternate universe where they are all part of a different ninja clan but still end up becoming friends and allies. And there might be a fanfic that focuses on their training days together, showing how they influenced each other's growth as ninjas.
One key element is the source of his overprotectiveness. Usually, it's his love for Sakura. He may have realized how important she is to him over time. Another element is how Sakura reacts to it. Sometimes she might be annoyed at first but then come to appreciate it. For example, in some fanfics, she initially tells Sasuke she can take care of herself but later realizes his actions are a sign of his deep affection.
I'm not really into lemon fanfictions as they often contain inappropriate content. But you can try looking on fanfiction.net or Archive of Our Own. Just make sure to check the ratings and tags to avoid any unwanted stuff.
One popular type might be those that focus on their team dynamics in new and creative ways within a non - romantic, friendly context. For example, a fanfiction could explore how they train together in a different setting, like a hidden forest with unique challenges. This can show their growth as ninjas and friends without getting into any inappropriate content.