There could be. In fanfiction, the concept of Harry Potter owning a ship can be explored in many ways. The ship might have magical abilities like being able to teleport within the wizarding world. Some fanfics might focus on how Harry discovers and uses these abilities for his adventures or to help the wizarding community.
He could have adventures like exploring uncharted magical islands. Maybe he'd encounter new magical creatures and have to use his wizarding skills to either befriend or fend them off. For example, he might come across a group of mermaids who guard a powerful magical artifact on an island.
There could be lost wizards who got stranded on the ship for some reason. Maybe they were on an expedition and something went wrong.
Some of the Hogwarts professors could also assist. Professor Flitwick could use his charms expertise to add special touches to the city - ship, like making the doors open with a unique charm. Professor McGonagall could use her transfiguration skills to transform materials into the needed shapes for the construction. And Neville could also play a role. He has grown into a powerful wizard, and his knowledge of herbology could be used to create a beautiful and functional garden on the city - ship.
Well, there are many unique Harry ship fanfics out there. For example, there could be a fanfic that pairs Harry with a Muggle character. This would introduce a whole new set of challenges as Harry tries to balance his wizarding life with his relationship with someone who has no knowledge of magic. Another unique one could be a time - travel based Harry ship fanfic. Say, Harry travels back in time and falls in love with a young Lily Potter's friend. And of course, a fanfic that has Harry in a relationship with a magical creature in a human - like form, like a veela or a centaur, which would be quite different from the typical ships in the Harry Potter fandom.
Redemption is also a theme. For example, in some fanfictions where Draco is a main part of a ship, his journey towards redemption while being in a relationship with another character is explored. It adds depth to the story and the relationship.
The plot could involve Harry building the ship with the help of his friends. They could all contribute their skills. For example, Hermione could use her vast knowledge of magic theory to ensure the ship's construction is perfect, while Ron could offer his practical skills. They might be building the ship to escape from some new dark force that has emerged in the wizarding world. Harry's ship would then be their means of getting away and finding a new place to start over. It could also be a ship that has special magical properties, like being able to fly or travel through time.
It could be a magical sailing ship. Maybe it has enchanted sails that can catch the wind of magic and sail across different magical realms. Or it could be a small, personal ship that he uses to explore hidden corners of Hogwarts lake.
It could be a sleek, enchanted schooner. With sails that can change color according to the magical energy around it. The ship might have a figurehead that comes to life and gives advice, like a wise old wizard.
You can start by searching on popular fanfic websites like Archive of Our Own (AO3). Use specific tags related to the ships you're interested in, for example, 'Harry/Hermione' or 'Harry/Draco', and then look for fics that have unique summaries or ratings. Another option is to join Harry Potter fanfic communities on social media platforms like Reddit or Tumblr. Members often share and recommend unique fanfics they've come across. You could also ask for recommendations in online Harry Potter fan groups.
You can find 'Draco and Harry ship fanfiction' on Archive of Our Own (AO3). It has a huge collection of fanfictions for various ships, including this one. Just search for the tags related to Draco and Harry, and you'll get a ton of results.