Maybe Hermione is injured while exploring some dangerous magical ruins. Snape is the only one around with the knowledge and power to heal her. As he heals her, they start to have deep conversations about magic, life, and their respective pasts, which in turn builds a connection between them.
Some Tumblr blogs also curate and share fanfictions. Search for Harry Potter fanfic blogs and then specifically look for the 'Hermione heals Snape' tag. However, be aware that the quality and content can vary greatly, so you may need to sift through a bit to find the ones that really appeal to you.
One common theme is redemption. Snape has had a rather complex and often villain - like portrayal in the original series, and in these fanfictions, Hermione's healing of him can be seen as a way to redeem him, both physically and emotionally.
In this fanfiction, the entire Weasley family could be involved in helping Hermione. Ginny, being Hermione's friend, would surely be there for her. They could talk about their experiences and Ginny could give Hermione the emotional support she needs. The Weasley boys, too. Fred and George might use their unique brand of magic to bring some cheer to Hermione's recovery. Ron, of course, would be by her side as well, perhaps feeling guilty if he thinks he had a part in her getting hurt.
In some fanfictions, Snape might use his advanced knowledge of potions to brew a special healing elixir for Harry. He could also use his magic skills, like a complex spell specifically designed to mend Harry's wounds, whether they are physical or emotional.
The 'Hermione Heals at the Burrow' fanfiction probably has a story full of care and recovery. Hermione may have faced some difficult situation before arriving at the Burrow. Once there, the family would rally around her. Ginny could be her confidante, sharing secrets and helping her deal with any emotional turmoil. The twins might use their humor to cheer her up. And all the while, Hermione is slowly but surely getting back to her strong self with the love and support of the Burrow's inhabitants.
Snape could also use his magical abilities in a more emotional sense. He might share his own past traumas with Harry, creating a bond of understanding that starts to heal Harry's broken spirit. By being vulnerable himself, he shows Harry that it's possible to move past pain.
Often, in the fanfic, it could be that Harry is injured during a Quidditch match. Snape, despite his dislike for Harry in some ways, realizes the importance of Harry to the wizarding world and heals him. There could also be a situation where Harry is affected by some dark magic in the Forbidden Forest. Snape, who has a deep understanding of dark magic, is the only one who can counter it and heal Harry. It might also happen that Harry is suffering from the after - effects of using powerful magic, and Snape uses his own unique magic to heal Harry's drained energy.
Well, Snape might heal Draco because of his own sense of morality. Despite his dark exterior, Snape has a code of ethics. Draco is still a student, and Snape may believe that every student should be given the chance to survive and learn from their mistakes. Additionally, Snape could be acting on behalf of Dumbledore in some way. Dumbledore often had complex plans, and Snape was his agent. Healing Draco could be part of a bigger plan to keep the balance in the wizarding world.
In some fanfictions, Snape might use his advanced knowledge of potions to create a special concoction to heal Harry. He could draw on his skills in Herbology as well to find rare ingredients for the potion.