One common theme is the revelation of secrets. Often, Harry discovers something about Snape that makes him want to fight, like Snape's connection to the Dark Arts or some hidden actions he has taken against Harry or his friends.
One popular 'harry fights snape fanfic' could be 'The Duel in the Dungeon'. In this fic, the fight is intense as Harry discovers some secrets about Snape and confronts him. It has great descriptions of the spells they cast at each other.
In the fanfiction, the magic might be more experimental. For example, Harry could use a spell he created himself during the fight with Snape, something that combines different elements of magic he has learned. Snape, on the other hand, might use some ancient and forgotten spells that were not in the original books. This would make the fight more unpredictable and exciting.
Snape's loyalty to Dumbledore would be a major driving force. He might see fighting Voldemort as fulfilling Dumbledore's final wishes. Snape would use the guidance and secrets Dumbledore shared with him to strategize against Voldemort. For example, if Dumbledore had some knowledge about Voldemort's horcruxes that he passed on to Snape, Snape could use that information to target them during the fight.
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.
In some fanfics, Snape might punish Harry because of his perceived insolence in class. Harry has a rebellious streak, and Snape, being strict, wouldn't tolerate any behavior that he deems disrespectful to his authority as a teacher.
Perhaps it's related to Harry's association with his father, James Potter. Snape had a long - standing grudge against James, and seeing Harry might bring back those bitter memories. So, whenever Harry does something that reminds Snape of James, like being overly confident or a bit of a troublemaker, he yells at him.
In some fanfics, Snape might hurt Harry out of his long - held grudges. Snape was in love with Harry's mother, Lily, and Harry being a reminder of James, who bullied Snape in school, could trigger his negative emotions. Also, Snape's loyalty to Voldemort in the earlier days in some fan - created scenarios might lead him to target Harry, who was seen as a threat to Voldemort's plans.
His friends like Ron and Hermione would surely be his allies. They have always been by his side in the original stories, so it's likely they'll be there in the fanfiction too, helping Harry in his fight.
Well, in such a fanfiction, Harry could have found a magical fire - producing object that gives him the ability to fight the dragon with fire. He might have to learn how to handle this new power quickly while in the heat of the battle. The dragon, on the other hand, would use its natural abilities like flying and breathing fire in return. It would be a battle of wits and power.