A plotline where Sasuke and Kakashi are forced to team up against a new and powerful enemy that neither of them can face alone. They have to put aside their differences and combine their unique skills. For instance, Sasuke's Sharingan and Kakashi's Sharingan - related techniques could be combined in a creative way to defeat the foe. This would involve a lot of strategizing and character development as they learn to trust each other more.
In a fanfiction, Sasuke could be kidnapped by a mysterious organization that is interested in his unique genetic makeup as an Uchiha. Kakashi would immediately start his investigation. He'd recall Sasuke's past enemies and possible motives. He might discover that the kidnappers are planning to extract Sasuke's chakra or use his body for some sort of experiment. Kakashi would then have to infiltrate their hideout, which could be filled with dangerous jutsu - based security measures.
Perhaps there's a mission where Kakashi and Sasuke are on opposite sides. Kakashi is following the orders of the village, and Sasuke is following his own path for revenge. In a confrontation, Kakashi uses his Sharingan - based techniques against Sasuke. Sasuke, not fully prepared to face Kakashi at that level, gets hurt. This would add more complexity to their relationship as teacher and student.
A plotline could be that there is a powerful new enemy that specifically targets their bonds. This enemy uses illusions and mind - control to try and turn Sasuke against Naruto, or make Sakura distrust Kakashi. They have to fight not only the physical attacks of this enemy but also the mental and emotional turmoil it causes within their group. In the end, they realize the true strength of their relationships and are able to defeat the enemy.
Perhaps a plotline where Kakashi is reincarnated in a world where the Akatsuki has achieved their goals. He would then be in a situation where he has to figure out how to oppose them or find a way to coexist in this new, darker ninja world.
One possible plotline could be Kakashi teaching them unique ninja skills. Since he has his own set of diverse abilities, he could pass on some of his more unorthodox techniques to Naruto, Sasuke, and Sakura. For example, he might teach Naruto a more refined version of the Rasengan, or help Sasuke better control his Sharingan powers. And for Sakura, he could train her in some of his stealth and assassination techniques, which would add a new dimension to her combat skills. Another plotline could involve Kakashi helping them deal with their personal issues. He could be a mentor figure for Naruto in understanding his loneliness and the importance of his role as a Jinchuriki. For Sasuke, Kakashi could play a key role in his journey to avenge his clan while also guiding him to not be consumed by hatred. And for Sakura, he could assist her in growing more confident in her abilities and not being overshadowed by her teammates.
One interesting fanfiction could be about Sasuke and Naruto going on a special mission with Kakashi as their guide. They face a powerful new enemy and have to rely on their combined skills and the wisdom Kakashi imparts. It might involve Sasuke using his Sharingan in new ways, Naruto's new jutsu, and Kakashi's strategic thinking.
One possible plotline could be Kakashi teaching Naruto some super - advanced jutsu that Naruto then uses to surprise his friends in a sparring match. For example, Kakashi might teach Naruto a special lightning - style jutsu that Naruto masters and combines with his Rasengan.
In some fanfictions, there could be a plot where Naruto and Kakashi get transported to a different dimension. In this strange new world, they have to find their way back home while facing various challenges. Along the way, they learn more about their own strengths and weaknesses and how their partnership is crucial.
Perhaps a plot where Naruto's determination in the face of some sort of 'heat' - like a difficult situation in the village, and Kakashi is there to guide him. It could involve Naruto learning new jutsus under Kakashi's tutelage while also dealing with his own growing pains.
Well, in some 'kakashi teaches naruto fanfiction', there might be a plotline where Kakashi teaches Naruto how to better control his chakra. This could involve some really intense training sessions deep in the forest. Also, Kakashi could be teaching Naruto about the art of stealth and infiltration, skills that Naruto doesn't have much experience with but are crucial for a ninja.