Another plot could be that a Supernatural entity, like an angel or a reaper, is observing the events on the Titanic. The story could follow their perspective as they watch the human tragedy unfold. They might be restricted by certain rules from interfering directly, but they still have some influence. For example, an angel could be subtly guiding certain passengers to safety without breaking the rules of non - interference too much.
Perhaps in some fanfiction, a character from Supernatural has a premonition about the Titanic sinking. They then try to use their powers to change the fate of the ship. This could involve trying to warn the crew or using magic to prevent the iceberg collision. There could be a lot of drama as they face resistance from those who don't believe them.
One interesting plot could be the Winchester brothers finally achieving a permanent peace in the afterlife. They've been through so much in the series, and in the fanfiction, they might get to rest without any new threats.
One interesting plot could be that the Supergirl characters find themselves in the Supernatural universe. Maybe Kara has to deal with demons and angels while trying to find a way back to her own world. She could team up with Sam and Dean to fight a common enemy, like a powerful demon who has a vendetta against both the Supernatural world and Kryptonians.
One common plot is exploring what could have happened if Madison had survived. Maybe she and Sam could have had a life together away from the hunting world, like living in a small town and trying to be normal.
Another plot could be that he is captured by a group of hunters who plan to keep him powerless. They try to use him as a bargaining chip with other demons or angels. But Lucifer, being clever even without his powers, tries to turn the situation around and manipulate the hunters to his advantage.
In some Hell House supernatural fanfiction, there might be a plot where a young, inexperienced medium is lured to the Hell House. The house tries to use the medium's power to break free from some ancient curse or seal. As the medium discovers the true horror of the house, they must fight against its influence and find a way to escape while also learning more about their own powers.
Well, in some Supernatural paralyzed fanfiction, there might be a story where a beloved character is paralyzed as a result of a spell gone wrong. Their friends in the Supernatural world might search for rare ingredients to create a cure. It could also involve the character having to adapt to their new state and still contribute to the fight against evil in some way, like using their knowledge of the occult to guide the others even while being paralyzed.
One interesting plot could be the combination of Naruto's world with Esdeath's power-hungry nature. Maybe Esdeath, as part of the peerage, tries to take over the Hidden Villages in Naruto's world using her extreme combat skills and sadistic tendencies. Another plot could involve Naruto trying to reform Esdeath, bringing out her good side if there is any, through his talk - no - jutsu.
Maybe in the fanfiction, the seven minutes is used as a time for a character to make a crucial decision. Like a hunter has to decide whether to trust a supernatural being they are locked in with. They might start off hostile but by the end of the seven minutes, they form an unlikely alliance.
Maybe a love interest betrays Sam. In the Supernatural world, a woman who Sam falls for could actually be an undercover agent of a dark force. She gets close to Sam, learns all his secrets, and then uses that information against him, perhaps leading his enemies right to him when he's most vulnerable.
Well, the Supernatural elements can add a whole new layer of mystery. For example, if there are ghosts on the Titanic in the fanfiction, they could be the spirits of those who died unjustly. The characters from Supernatural might be able to communicate with them and find out secrets about the ship's construction or the events leading up to the sinking that were covered up.