Well, perhaps Harry stumbles upon a goblin in a dangerous situation, like being trapped by dark wizards who want to steal the goblin's magic artifacts. Harry uses his skills and spells to fend off the bad guys and rescue the goblin.
It could be that the Goblin King's magical artifacts are being stolen one by one, and this is weakening his realm. Harry Potter gets wind of this and decides to help. He teams up with some of his Hogwarts friends like Hermione and Ron. They use their combined knowledge of magic and spells to track down the thieves and return the artifacts to the Goblin King, thus saving his kingdom.
A group of dark creatures like Dementors could be the antagonists. They might be after the young goblin because goblins have a unique life force that can sustain Dementors in a way other prey cannot. Harry Potter would have to face his own fears while using powerful Patronus magic to drive the Dementors away and save the goblin.
Well, perhaps the young goblin is in danger from some dark wizards who want to use its unique magical abilities for evil. Harry Potter, being the hero he is, stumbles upon the situation and uses his skills and magic to fend off the bad guys and save the goblin. Maybe he discovers the goblin has some information crucial to the wizarding world's safety too.
It could be a dark wizard who has a vendetta against goblins. This wizard might see goblins as a source of power or wealth and wants to enslave them. So when Harry tries to save the goblin, this dark wizard becomes the main obstacle.
It could be a powerful dark wizard who has a grudge against the goblins. Maybe he wants to steal the goblin's vast treasures and is willing to get rid of the Goblin King to do so.
Well, maybe the goblin child is in danger because of some dark wizards who want to use the goblin's skills for evil. Harry Potter stumbles upon this situation and decides to protect the child. He could use his magic skills like the Patronus charm to fend off the dark wizards and then find a safe place for the goblin child, perhaps among the friendly goblins in Gringotts.
In fanfiction, goblins can help in various ways. For example, they might assist Harry Potter with getting access to certain Gringotts vaults that hold crucial items or information. Goblins are known for their skill in handling gold and guarding treasures, so they could use their knowledge to help Harry in his fight against Voldemort by providing him with financial resources or magical artifacts that were previously hidden away.
Harry's sense of justice would be further emphasized. Saving the goblin child shows that he doesn't discriminate based on species. His confidence would also grow as he overcomes the challenges in saving the child. He would become more respected among the goblin community too.
Some fanfictions create entirely new goblin characters. For example, there could be a young goblin prodigy who befriends Harry. This character could have extraordinary skills in metal - working magic, which is something goblins are known for in the Potterverse. They might use their skills to create powerful magical items for Harry or help him in his battles.