A more complex plot development might involve the origin of the snake. It could be a dark wizard's pet that was set loose deliberately to target Severus. After Hermione saves him, they could team up to find out who was behind it. This would lead them on a journey where they have to use both of their skills. Hermione's book - knowledge and Severus' experience in the dark arts. Along the way, they might discover secrets about each other and their families that were previously unknown, which could further deepen their relationship, whether it becomes a friendship or something more ambiguous.
One possible fanfic could be 'The Unlikely Rescue'. In it, Hermione uses her quick thinking and extensive knowledge of potions to counteract the snake venom that Severus has been bitten with. She manages to find the right ingredients in the Forbidden Forest and brews a makeshift antidote just in time.
One possible plot could be that Ron is under the influence of a dark spell that makes him act aggressively towards Hermione. Severus, being observant, notices this and steps in to protect Hermione. He uses his potions knowledge to create an antidote for the spell on Ron.
Well, it could start with Severus being a vampire in secret and Harry gradually finding out. Maybe Severus initially resists the urge to feed from Harry but then some situation forces him to. For example, he might be injured and need Harry's blood to heal.
Severus might be developed as a more complex and empathetic character. By saving Hermione from Ron, he shows a side of himself that is protective and caring, which is different from his usual cold exterior. This could be a turning point in how the other characters view him.
One possible plotline could be that Lockhart attempts to use Harry for some self - promoting stunt that goes horribly wrong, and Severus steps in to rescue Harry from the immediate danger. For example, Lockhart might try to make Harry participate in a dangerous magic display for his own glory, but Severus, seeing the real danger, intervenes.
One possible plot development could be the initial shock and confusion for both Harry and Hermione. They would have to deal with the reactions of their friends, like Ron, who might be very surprised or even a bit jealous. Then they'd need to figure out how to balance their new situation with their fight against Voldemort or other magical threats. Another aspect could be how they prepare for the baby, from finding a safe place to live to getting all the necessary baby supplies in the wizarding world.
One possible plot development could be that after saving Naruto, Madara tries to mentor him. He sees Naruto's potential and wants to shape him into an even greater ninja, sharing his own knowledge and skills that have been honed over years.
One possible plot twist could be that the troll is actually under the control of a dark wizard. So when Harry saves Hermione, they realize that there is a much bigger threat at hand. Another twist could be that the troll turns out to be a transformed Hogwarts student, and they have to find a way to reverse the spell instead of just fighting it.
Another way Severus could save Hermione is by using his knowledge of the Dark Arts in a positive way. If she was hurt by a Dark spell from Ron (in the context of the fanfic), Severus might be able to counteract the spell's effects. He has extensive experience with Dark Arts spells, so he could figure out what spell Ron used and then use a counter - spell to reverse the damage.
In this kind of fanfic, one possible scenario could be that Harry uses his quick thinking and magical skills. For example, he might use a stunning spell on the troll just in time to stop it from harming Hermione. Another scenario could be that Harry lures the troll away from Hermione, using his knowledge of the troll's behavior. Maybe he throws something noisy in the opposite direction to draw the troll's attention.