In some fanfictions, the theme of discovery is present. They might find a new type of Pokemon or a hidden power within their existing Pokemon. There could also be a theme of mystery, for example, if they encounter a strange phenomenon in the Pokemon world that they need to solve. And of course, the theme of loyalty between them and their Pokemon is often explored, showing how their Pokemon support them in different situations.
Perhaps a story where Allister is having trouble with his confidence in battles, and Bea decides to train him. She shows him new fighting techniques for his Pokemon, and in return, Allister teaches her how to better understand the more mysterious aspects of Pokemon battles. This way, they both grow as trainers and form a strong friendship that helps them face tougher opponents in the future.
Given Allister's love for Ghost - type Pokemon which are often associated with the unknown and mystery, and Bea's focus on Fighting - type Pokemon which represent strength and directness, their personalities could clash at first. However, as they get to know each other through their shared love for Pokemon, they would find common ground. Allister might share his insights about the more ethereal aspects of Pokemon battles, and Bea could show Allister how to be more confident in the physical aspects of battling, creating a harmonious relationship in the long run.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). There are often a lot of Pokemon fanfictions there, and you can specifically search for ones involving Bea and Allister. Another option is FanFiction.net. Just use their search function and type in the relevant keywords.
Adventure is also a popular theme. Writers like to take Bea and Allie on all sorts of adventures, whether it's in a fictional world, a different time period, or just in a new place in their own town. It makes for exciting stories.
One interesting Allister Pokemon fanfic could be 'Allister's Ghostly Adventures'. It might explore his unique relationship with Ghost - type Pokemon in more depth, like his encounters with different spirits in the Pokemon world. Another could be 'Allister's Hidden Powers', which delves into any potential special abilities he has that haven't been fully explored in the official games or anime.
A great story could involve Allister traveling to an ancient, haunted place in search of a rare and powerful ghost - type Pokemon. Along the way, he has to face his own fears and learn more about the history of the Pokemon world. He could encounter various challenges like solving puzzles related to the ghosts of the past trainers who once visited that place.
A well - crafted plot involving Allister's Pokemon battles is also appealing. For instance, if the battles are described in great detail, with the use of different Pokemon moves and strategies, it can be very engaging. It could also include unexpected twists in the battles, like a new move his Pokemon learns at a crucial moment.
One common theme might be self - discovery. As they interact, Mae and Bea could learn more about themselves. Also, family dynamics could play a role. For instance, how their families influence their relationship or how they create a new 'family' of sorts with each other. In some fanfics, there could also be a theme of overcoming obstacles, whether they are external like a villain or internal like personal insecurities.
One common theme is the exploration of grief among the trainers. When a Pokemon dies, it can shatter the bond between the trainer and the Pokemon. Trainers might have to come to terms with their own mortality as well, since the Pokemon was often like a partner in their adventures.
Some common themes include the mystery of the unborn Pokemon. Writers might create a sense of wonder about what kind of abilities or characteristics the new Pokemon will have. Another theme is the role of the trainer. The trainer might have to learn new ways to take care of the pregnant Pokemon, like adjusting its diet or exercise routine. There's also the theme of the natural cycle. It shows how pregnancy and birth are a normal part of the Pokemon world's cycle of life, and how all the elements in the environment, from other Pokemon to the terrain, play a role in this process.