Often, a fanfiction might have Naruto severely wounded during a training accident that goes horribly wrong. He might be trying a new and extremely powerful jutsu that he's not fully mastered yet. This could result in him being in a critical condition. His friends and mentors then have to figure out how to heal him and deal with the consequences of his over - ambition in training.
Another plotline could involve Naruto being injured as a result of a trap. Maybe he's exploring an ancient ruin in search of some power to help protect the village and he triggers a hidden mechanism. This could lead to him being severely wounded, and his friends would need to come rescue him while also trying to figure out how to disarm any other potential threats in the area.
One common plotline is a powerful enemy ambush. For example, Naruto might be on a solo mission and get caught off - guard by a new, extremely strong villain. This villain could use some unknown jutsu to severely wound Naruto. Another plotline could be Naruto sacrificing himself to protect the village. He might take on a massive attack meant for the Hidden Leaf, resulting in him getting severely injured but saving the village in the process. And sometimes, it could be due to a failed experiment. Maybe he was trying out a new and risky form of his chakra manipulation and it backfired, leaving him severely injured.
Sakura is very likely to help. She's a skilled medical ninja and has always been there for Naruto. She would use her medical jutsu to try and heal his wounds. Kakashi too. He has a lot of experience and would be able to protect Naruto while he's injured. Also, Sasuke might come to Naruto's aid. Despite their past differences, they have a deep bond, and Sasuke would not let Naruto die if he could help it.
Well, he might be saved by Ladybug using her Lucky Charm in a very creative way. Maybe she'll have to combine it with some new powers she discovers just for this emergency.
Some fanfictions explore the idea of Naruto being betrayed by a new character introduced into the story. This new character could be secretly working for an enemy and manages to turn Naruto's closest allies against him by using their insecurities. This creates a complex web of relationships where Naruto has to fight not only the external threats but also the internal ones within his group.
One common plotline is Naruto's slow recovery from a severe injury. He has to overcome physical pain and weakness, all while trying to keep his spirits up. Another is that he discovers a new power or ability while in the hospital, maybe something related to his chakra that he can only access when he's in a weakened state.
One common scenario could be during a battle with an akumatized villain. Maybe the villain has a new power that catches Adrien off - guard and he gets wounded while protecting Ladybug. Another situation might be in a non - akuma related accident. For example, he could be exploring an old building as Chat Noir and some part of the structure collapses on him. Also, in some fanfictions, there could be a plot where a new enemy specifically targets Adrien and manages to wound him during an ambush.
One possible plotline could be that Danny gets into a fight with a new and extremely powerful ghost. This ghost has some sort of unique power that can cause severe harm to Danny, like a draining ability that saps his energy and leaves him severely injured. He then has to struggle to hide his condition from his friends and family while trying to find a way to defeat the ghost.
A typical plotline in 'angry naruto fanfiction' is Naruto's anger due to the village's past actions against him. For instance, the way he was ostracized as a child. His anger then causes him to either distance himself from the village or try to make it a better place by changing its ways. Sometimes, his anger is also sparked by threats from outside forces to the village, but the village elders don't believe in him to handle it, which makes him really angry and he takes matters into his own hands.
One common plotline could be Kurenai trying to keep Naruto away from certain dangerous missions. She might think he's not ready yet and be overly protective in the fanfiction.