I'm not sure about a specific one named exactly like that, but in general, such fanfictions often explore how Harry's character would develop if he had nen powers. Maybe in some, he uses nen to fight Voldemort in a more unique way than with just spells. He could use nen to enhance his physical abilities, like speed and strength, during duels.
One popular 'Harry Potter uses nen' fanfiction could be 'The Nen - Powered Wizard'. It combines the unique magic system of nen from Hunter x Hunter with the magical world of Harry Potter in an interesting way. The story might have Harry discovering nen abilities and using them to solve problems in Hogwarts that he couldn't with regular magic.
Fanfiction.net is also a good place to look. There are thousands of Harry Potter fanfictions there. However, the search might be a bit trickier as it has a large volume of content. But if you are persistent and look through the relevant categories like 'Harry Potter' and then use the advanced search options to include 'nen' in the search terms, you might find what you're looking for.
One popular 'Harry knows nen' fanfiction could be 'The Nen - Enabled Wizard'. It explores how Harry's newfound nen abilities change his approach to magic and his battles at Hogwarts. Another might be 'Harry and the Nen Realm', which delves into a world where Harry discovers a connection between nen and the wizarding world's hidden secrets. There's also 'Nen - Powered Harry Potter', where his nen powers give him an edge in dealing with dark wizards.
I'm not sure about a specific one named just 'Harry Potter uses Legilimency' but in general, you can find great fanfictions on platforms like Archive of Our Own. If you search for the tag 'Harry Potter' and 'Legilimency', you'll come across many stories. Some might show Harry using Legilimency to solve mysteries, like finding out the true identity of a mysterious figure at Hogwarts. Others could explore how his use of this mind - reading ability affects his relationships, for example, with Hermione and Ron when he starts to read their unspoken thoughts.
One possible 'Harry Potter uses circles' fanfiction could be about Harry using circular spells or magical formations. Maybe he discovers a new form of magic that involves circles to protect Hogwarts from a new threat. It could be a really creative take on the magic system in the Potterverse.
One popular 'Harry Potter uses rune magic' fanfiction is 'The Rune - Bound Wizard'. It delves deep into how Harry discovers and masters rune magic in a way that is both exciting and true to the original Potterverse feel. Another one could be 'Runic Resurgence in Hogwarts' which focuses on Harry using rune magic to solve mysteries within the school.
There is 'Wandless and Free' which focuses on Harry's journey to master wandless magic. In this fanfiction, he meets an old wizard who teaches him the ancient ways of magic without a wand. It also delves into how this newfound power changes his relationships with his friends and enemies alike. It's full of exciting plot twists and character development.
One possible fanfiction could be where Harry Potter discovers an ancient scythe in the Forbidden Forest. He realizes it has some magical powers and uses it to defend Hogwarts against a new dark threat. Maybe it can cut through dark magic like a hot knife through butter.
One interesting idea could be the combination of the magic system in Harry Potter with the nen abilities from Hunter x Hunter. For example, a character might use nen to enhance their existing wizarding spells, making them more powerful or having unique effects. Another idea could be the introduction of nen-based creatures into the Harry Potter universe, which would add a whole new level of danger and mystery.
In the fanfiction 'Harry's Time - Turner Escapades', Harry uses the Time - Turner to fix some mistakes in the past. The story is well - written and delves deep into the implications of time - traveling in the Harry Potter universe. It also has some great interactions between Harry and other characters like Dumbledore and Hermione.
The character interactions can be quite fascinating. Imagine Harry Potter characters like Hermione trying to understand and perhaps even study nen, or characters from Hunter x Hunter like Gon exploring Hogwarts. It could lead to some really unique friendships and rivalries. Also, the plot possibilities are endless. For example, a dark wizard using nen to enhance their dark magic, and the heroes having to figure out how to counter it with both their magic and nen knowledge.