Kakashi could also be there to help. He has a lot of experience and is very protective of Naruto. He might use his strategic mind to keep Naruto safe while waiting for more help to arrive, and also offer some words of wisdom to Naruto during his recovery.
Sakura is a very likely character. As a skilled medical ninja, she has the knowledge and ability to treat Naruto's injuries. In many fanfictions, she is often the first to rush to his side and use her medical jutsu to stabilize him.
Sasuke is very likely to be involved. Given their complex relationship, Sasuke could be the one who finds Naruto severely injured and has to make a choice between helping him or leaving him. Another character could be Sakura. As a medic - ninja, she would be the one to try and heal Naruto's severe injuries. Kakashi too might be involved, either as a mentor figure who tries to figure out what happened to Naruto or as someone who has to step in to protect Naruto from further harm while he is injured.
Often, his friends like Sasuke, Sakura, and Kakashi might come to his aid. Sakura, being a medical ninja, would likely be the first to start treating his injuries. Sasuke could use his Sharingan to help in some way, perhaps to find the root of the injury or fend off any threats while Naruto is injured. Kakashi, with his experience, would also offer strategic advice on how to deal with the situation.
Gil could also be there to assist. He's Harry's friend and fellow crewmate. Gil is not as clever as Harry in some ways but he's very loyal and strong. He would do things like fetch water, find food, and stand guard while Harry is recovering.
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.
Sakura would definitely be involved. As a medical ninja, she would be at the forefront of trying to heal Naruto. Sasuke might also be there, either helping in the fight that led to Naruto's injury or coming back to the village to see his old rival. Kakashi would also be around, using his experience to strategize how to protect Naruto while he's injured.
In some fanfictions, Jane Foster could play a role. If she's around Asgard at the time, being a scientist, she might have some knowledge or technology that could be used to treat Loki's wounds. Also, Valkyrie could be a helper. She's a fierce warrior and has a sense of honor. She might see Loki's injury as a chance to prove her worth or as a debt she needs to repay if Loki had previously helped her in some way. And of course, Frigga, if she were still alive in the fanfiction, would be a great source of comfort and healing magic for Loki.
In some fanfictions, Naruto's recovery could be a long and arduous journey. He might have to go through intense physical and mental training while recovering. The author could also introduce some kind of ancient and forgotten medical knowledge that is used to treat his severe injuries. His recovery might also be tied to some prophecy or hidden power within him that is awakened due to the near - death experience.
Even some of the antagonists could potentially help Jaune if there is a complex relationship developed in the fanfiction. For example, if an enemy realizes that Jaune's death or continued injury would disrupt some sort of balance, they might step in to heal him, albeit reluctantly.
The Hokage at the time, whether it's Tsunade or someone else, would likely get involved. They would allocate resources and ensure that the best medical care is provided. Additionally, some of the older ninja who knew Kakashi since he was young, like Iruka, might offer moral support and assist in any way they can, like gathering information or running errands related to his treatment.
Bobby could also be a key figure. He's like a father figure to the boys and has a wealth of knowledge. He might know of some old remedies or be able to point them in the right direction to find a way to heal Dean. Charlie could also pitch in. She's smart and resourceful and could use her hacking skills to find information related to Dean's injury.