A really interesting plot could be that a goblin mate has a unique magical ability that is the key to saving Hogwarts from a new dark threat. The wizarding characters initially doubt the goblin but gradually come to realize their importance and the power of their bond.
A great plot could be that the goblin is a time - traveler. It has come from a future where Voldemort has won and is trying to change the past. The goblin teams up with Harry, using its unique goblin magic and knowledge of the future to give Harry an edge in the fight against the dark forces. They might have to travel to different magical locations and enlist the help of other magical creatures.
One plot idea could be that Fenrir's mate is a powerful witch who has the ability to control his werewolf side. She could use her magic to soothe him during his transformations and together they try to find a way to end the discrimination against werewolves in the wizarding world. This would involve them facing many challenges, such as the Ministry of Magic's strict laws and the prejudice of other wizards.
One idea could be a werewolf character finding their true mate among the Harry Potter characters. Maybe a werewolf who has always felt like an outcast in the wizarding world finally meets someone who accepts them completely. This could lead to a story of self - discovery and acceptance for both the werewolf and their mate.
One idea could be that the Head Goblin discovers a long - lost magical artifact hidden deep within the vaults of Gringotts. This artifact has the power to change the balance of magic in the wizarding world. Another could be that the Head Goblin forms an unlikely alliance with Harry Potter to protect Gringotts from a dark wizard who wants to steal all the gold and magical items stored there. Or perhaps the Head Goblin has a secret past related to Harry's family, and this connection unfolds throughout the fanfiction.
One plot idea could be that the Goblin King has a secret alliance with a dark wizard that Harry and his friends have to uncover. They might find out through a series of mysterious events and clues left in Gringotts. Another could be that the Goblin King decides to rebel against the wizarding world's control over goblin - made artifacts and starts a movement for goblin rights, with Harry caught in the middle as he tries to maintain peace. A third idea is that the Goblin King discovers a powerful ancient magic that could change the balance of power in the wizarding world and Harry has to either stop him from misusing it or convince him to use it for good.
In some goblin debt fanfics, the plot might revolve around how the goblin debt affects the wizarding economy. For example, if Harry's debt is so large that it starts to influence the value of Galleons. The goblins could use this debt as leverage to gain more control over Gringotts' operations in relation to the wizarding world. Harry then has to find a way to break free from this economic stranglehold.
Jasper could be a time - traveler OC. She travels back in time and accidentally disrupts the timeline where she meets a young Harry Potter. At first, Harry is suspicious of her, but as they work together to fix the timeline, they form a bond. As mates, they have to deal with the consequences of their actions in the time - travel, such as preventing certain events from changing too much and also protecting their relationship from those who would oppose a time - traveler being involved with Harry Potter.
A possible plot for Harry and Tom mate fanfiction is that they are both sent on a special mission by Dumbledore. Along the way, they have to rely on each other's strengths. Tom might use his intelligence and cunning, while Harry uses his courage and loyalty. They could also encounter magical creatures that they have to work together to defeat. This would force them to put aside their differences and form a bond. And as they complete the mission, they realize that they can learn a lot from each other.
One idea could be that Harry discovers a magical realm where Jareth rules and they initially clash due to their different personalities. But as they face common threats, like a dark force trying to invade both their worlds, they start to understand each other and form a bond. Another could be a story where Harry is transported to Jareth's world and has to learn the rules there to survive, and Jareth takes an interest in him because of his unique magic from the wizarding world.
Perhaps Bill's mate is an Animagus. She turns into a beautiful, rare animal like a phoenix. Bill discovers her secret accidentally and they bond over their love for magic and the secrets it holds. They go on adventures together, with her in her Animagus form sometimes, exploring the hidden corners of the wizarding world.