He could get a wand with a phoenix feather core from a very special phoenix. This would make his wand extremely powerful and have a strong connection to the element of fire, symbolizing his courage.
Well, perhaps they'll meet a really eccentric wandmaker. This wandmaker might have all sorts of unique wand - making techniques. Maybe they'll use rare magical woods or cores that are not commonly used. Harry could be in for a real adventure in this fanfic. He might discover a whole new side to wand - making that he never knew before.
The custom wand in the fanfic could lead to a whole new set of adventures for Harry. It could be made from a rare material that attracts the attention of dark wizards who want to steal it. This would put Harry in a dangerous situation where he has to protect his wand and himself. The wand might also have a mind of its own and guide Harry to places he never thought of going, like hidden chambers in Hogwarts or ancient magical sites outside of the school.
There's a chance that the maker is a new character, an old hermit wizard who lives deep in the Forbidden Forest. He has been observing Harry from afar and realizes that the wands available in the regular market are not sufficient for him. So, he uses his knowledge of forgotten magics to craft a custom wand just for Harry.
Maybe an old, reclusive wand - maker who has been waiting for the right wizard to come along. This person could have a special intuition about wands and see something unique in Harry.
Well, if Sirius takes Harry to Voldemort in a fanfic, it would be a huge deviation from the normal story. One possibility is that Sirius is trying to make some sort of deal with Voldemort to save others. But Voldemort is not one to be trusted. Harry, being the Boy Who Lived, is a valuable asset to Voldemort for his own dark purposes. It could lead to a tense stand - off where Harry has to use his own wits and magic, even at such a young age, to try and escape the clutches of the Dark Lord.
Well, he might discover new magical abilities. The custom wand could be made of unique materials, like a core from a rare magical creature. This could give him an edge in spells.
Well, it could be described in various ways. Maybe it has unique carvings on it, like ancient runes or symbols related to Harry's personal journey. It might be made of a special wood that's not common in the regular wand lore, like a wood from a magical tree only found in a hidden forest.
In this fanfic, Sirius could be tipped off that the Dursleys are planning to send Harry away to some even worse place. So he swoops in. They flee to a remote wizarding village. There, Harry meets other wizards and witches who are sympathetic to his cause. Sirius helps Harry train in combat magic, as he anticipates future battles. Harry also gets to explore his magical heritage more freely without the Dursleys' restrictions.
In the fanfic, Sirius and Harry leaving England could lead them to a hidden magical island. There, Harry could learn different kinds of magic that are not taught at Hogwarts. Sirius would be able to protect Harry better as they are far away from the threats in England. They might also start a new life where Harry can grow up without the constant fear of Voldemort's followers finding him.
One idea could be a wand made from a phoenix feather core and ebony wood. In fanfic, it could be a wand passed down through generations and have special powers like being able to communicate with phoenixes. Another idea is a wand with a mermaid scale core and coral - like wood. It might be able to control water elements and be used by a wizard who has a special connection to the sea.