In a fanfiction, the lemons could be used as a form of currency or trade item between the Pokemon of the two regions. A Pokemon from Leaf Green might offer a lemon to a Pokemon from Pokemon X in exchange for a rare berry or a special ability. This interaction could then create a whole network of trade and cooperation between the different Pokemon species from both regions.
Well, friendship is a big theme. Writers like to explore the relationships between the trainer and their Pokemon as well as between different trainers. Also, the mystery aspect is popular. For example, there could be mysteries about hidden Pokemon or secret areas in the Kanto region. And of course, the growth of the trainer, both in terms of skills and character, is often a central theme in these fanfictions.
Yes, there are many. You can start by looking on fanfiction platforms like FanFiction.net. There are various stories that focus on the adventures in Pokemon Leaf Green, such as ones that explore the unique Pokemon in the Kanto region, the gym battles, and the friendship between the trainer and their Pokemon. These stories stay true to the spirit of the game and are family - friendly.
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.
I recommend the following Pokémon novels to you. They all have legendary Pokémon!
1. "Elf: The Opening Ambush Hunter": The protagonist's first Pokémon was a small fire dragon.
2. [Pokémon: Lightning Bird at the beginning of the game: The legendary Pokémon Lightning Bird was drawn at the beginning of the game.]
3. "Musashi of the Elves": Musashi and his Abbot are also one of the classic characters in elf novels.
4. [Ten Artifacts of Pokémon Evolution]: There are divine beasts like the Three Pillar King and the Hell Dragon.
I hope you like my recommendation. Muah ~
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.
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.