One possible adventure is that they travel to a different dimension. The goblin friend has a special ability to open portals, and they end up in a dimension where magic works differently. There, they have to find their way back while also helping the local magical beings who are being oppressed by a powerful entity. Or they could go on an adventure to a hidden island where a powerful magical creature lives, and they need to get an ingredient from it to make a potion that can save Hogwarts from a curse.
Well, in fanfiction about Harry Potter having a little goblin friend, it could be really interesting. Maybe the goblin friend is an outcast in the goblin society and Harry befriends him. They might go on adventures together in the Forbidden Forest, looking for rare magical plants. The goblin could have special knowledge about the forest that Harry doesn't. And they could also form an alliance against the Death Eaters or other threats in the wizarding world. It would add a whole new dimension to Harry's experiences in Hogwarts and beyond.
How about 'Glim'. It has a nice, short and goblin - like sound to it.
Harry could have adventures where he tries to help his parents' ghosts pass on to the afterlife properly. This would involve solving mysteries about their untimely deaths. Along the way, he'd meet other ghosts with their own stories, and they could join him on his quest. He might also find ancient spells that can interact with the ghostly world more fully during these adventures.
Maybe he's really good at forging magical items. Given that goblins are skilled at working with metals and creating magical objects in the official lore. In fanfiction, this little goblin friend could use his skills to create special items for Harry, like a unique wand or a charmed piece of jewelry that has some special power. He would also be a bit grumpy at times, especially when wizards don't respect goblin ways, but still be loyal to Harry as a friend.
One possibility could be that the goblin friend helps Harry discover a hidden magical artifact. Goblins are known for their knowledge of magical items in the Harry Potter world. So this goblin friend might lead Harry to a long - lost family heirloom of the Potters that has some powerful magic which could help Harry in his fight against Voldemort.
They could go on an adventure to find a missing magical artifact that has fallen into the Muggle world. Gibbs' skills in tracking and Harry's knowledge of magic could be combined to track down the artifact before it causes any harm.
He could go on adventures to discover hidden vaults within Gringotts. Maybe there are vaults that have been lost for centuries, filled with ancient and powerful magical artifacts. Harry could search for these vaults, facing various traps and puzzles along the way, similar to the challenges he faced in the Philosopher's Stone.
They could go on a mission to explore an ancient and mysterious ninja temple. This temple is said to hold powerful ninja artifacts. Along the way, they would face various traps and enemies. Naruto's new friend, say it's Sasuke, could use his Sharingan to detect hidden mechanisms, while Naruto uses his shadow clones to scout ahead. It would be a dangerous but exciting adventure filled with ninja action.
In a fanfiction scenario, Harry might name his goblin friend Pebble. Harry discovers the goblin while he is wandering near the edge of the wizarding world. The goblin is small and seems lost. Harry takes him under his wing and names him Pebble because he is as tough as a pebble. The goblin, Pebble, then reveals to Harry some ancient goblin magic that has been lost to the wizards. With this knowledge, Harry uses it to fight against a new dark force that is emerging in the wizarding world, and their friendship is strengthened through these shared experiences.
In the fanfiction, Harry with his custom wand could have adventures in the world of magical creatures. He could communicate with creatures that were previously unapproachable, like the giant serpents in the Forbidden Forest. His custom wand might have a special ability to understand and interact with these creatures on a deeper level. He could also use it to protect these creatures from those who would harm them, leading to a series of exciting and dangerous encounters.