One interesting plotline could be the protagonist's first encounter with a rare Unova Pokemon. It might be a unique take on how they bond and start their journey together.
I'm not sure specifically as it's a fanfiction, but likely it has a trainer as a main character.
One interesting plotline could be a trainer's journey to discover a rare and powerful Pokemon in the Kalos region. They might face many challenges along the way, like battling against powerful trainers who also seek the same Pokemon.
One interesting plotline could be Ash and Serena getting lost in a mysterious new region full of never - before - seen Pokemon. They have to rely on each other's skills to survive and find their way out.
I'm not sure specifically as there could be many different plots in this fanfiction. It might involve the adventures of the trainer in the Kalos region, encounters with new Pokemon, and the journey to become a Pokemon master.
Since it's a fanfiction about Pokemon in the Alola region, it could involve the main character exploring different islands. They might take part in the island challenges, meet unique Alola Pokemon forms, and have interactions with the local characters. For example, they could team up with Hau or Lillie to battle Team Skull or discover some hidden secrets in the Alola region's beautiful landscapes.
There are also fanfictions where the OC is a traveling merchant in Unova. They trade rare Pokemon items and in the process, they come across a group of Pokemon thieves. The OC uses their wits and the help of their trusty Pokemon partner, which could be an OC - created unique Pokemon hybrid, to outsmart the thieves and return the stolen items to their rightful owners.
In such a fanfiction, Ash and May could encounter new and rare Pokemon in Unova. They might face tough battles against powerful trainers and gym leaders. For example, Ash could use his Pikachu in unique strategies against Unova's electric - type Pokemon that have different abilities compared to those in other regions.
The theme of discovery is quite common. Ash discovers new Pokemon species, new battle strategies, and new aspects of the Unova region. There's also the theme of competition, as he battles against various trainers in Unova. His interactions with these trainers and how he learns from each battle is a key part of many fanfictions.
One interesting plotline could be Ash encountering a new and extremely rare Pokemon that has unique abilities. This Pokemon might initially be hostile but gradually form a bond with Ash as they overcome various challenges together.
One interesting storyline could be about a trainer who discovers a rare and powerful Pokemon in the Unova region that has been lost for centuries. This Pokemon could have unique abilities that change the way battles are fought in the fanfic.