Articuno, Zapdos, and Moltres are quite common. Their elemental powers and the mystery surrounding them make for great fanfiction material. Ash might encounter them during his travels and have to either help them or face off against them in some way.
One of the Legendary Pokemon could be Giratina. Despite its somewhat dark and otherworldly nature, Giratina might be intrigued by Ash's light - heartedness and his ability to make friends with all kinds of Pokemon. Dialga and Palkia could also be part of the harem. Dialga, with its control over time, might see Ash as an important factor in the future of the Pokemon world. Palkia, in charge of space, could be interested in how Ash navigates different regions and spaces in his journey. And don't forget about Ho - Oh. Ho - Oh is a symbol of hope and might see Ash as a bringer of hope in the Pokemon world, thus joining his harem.
Arceus is quite popular. Given that it's considered the creator of the Pokemon universe in the official lore, it often has a significant role in fanfictions. Mewtwo is also very common. Its powerful psychic abilities and complex backstory make it a favorite for fanfic writers to explore. Another popular one is Lugia. With its majestic appearance and its connection to the sea, it's often a central figure in many stories.
There are also fanfictions where Ash catches Rayquaza. This could be set during a time when the sky is in chaos due to some dark energy. Rayquaza is drawn to Ash because of his pure heart and determination. Ash, with his usual courage, teams up with his pokemon to assist Rayquaza in restoring balance. As a result, Rayquaza allows Ash to catch it.
Well, reacting to a Pokemon fanfic can be really exciting. First, I might focus on how the author has developed the characters. If they manage to stay true to the original Pokemon personalities while also adding their own twists, it's great. For example, if Pikachu in the fanfic shows an unexpected fear of water, which is different from the usual brave Pikachu we know, but is explained well in the context of the story. Then, I'd look at the plot. Is it an adventure that takes us to new and uncharted regions in the Pokemon world? Or is it a more character - centered story about the bond between a trainer and their Pokemon? Another aspect to consider is the writing style. If it's descriptive and makes me feel like I'm right there in the Pokemon world, with vivid descriptions of the landscapes and battles, it's a great fanfic.
Mewtwo is also very popular. Given its origin as a genetically - engineered Pokemon, a human could interact with it in many ways. Maybe a human scientist wants to study Mewtwo further, or a young trainer tries to befriend Mewtwo and help it come to terms with its existence and powers.
In Ash's adventures in legendary Pokemon fanfics, he often has extraordinary encounters. For example, he might form unique bonds with legendary Pokemon that are not part of the main canon. These fanfics can take his story in new and exciting directions, like having him team up with a Mewtwo in a way that defies the normal Pokemon - trainer relationship. It's all about exploring the untapped potential of his character in the context of the amazing world of legendary Pokemon.
The appeal lies in seeing Ash in new and exciting situations. With legendaries involved, his journey becomes more epic. It's like taking the underdog story of Ash in the anime and supercharging it.
In Ash-centered legendary Pokemon fanfiction, often Ash has extraordinary adventures. He might form unique bonds with legendary Pokemon that are not seen in the official storylines. For example, he could befriend a Mewtwo and together they face off against an evil organization trying to clone more powerful Pokemon. These fanfictions allow for a lot of creativity, expanding on Ash's character and his relationships in the Pokemon world.