It's a bit hard to recommend specific Bakugan Bans Brother Harem fanfiction stories without having read a large number of them. But generally, stories that explore the emotions and conflicts within the harem concept can be interesting. For instance, a story that shows how the different characters in the harem deal with jealousy or competition for the main character's attention. Also, stories that stay true to the Bakugan universe in terms of its rules, powers, and the overall lore are often more appealing. You might also want to check out stories that have a good balance between the harem aspect and the action - packed Bakugan battles, as this can create a more dynamic and engaging reading experience.
You can try some popular fanfiction websites like FanFiction.net or Archive of Our Own (AO3). They usually have a wide range of fanfictions including those related to Bakugan. Just search for 'Bakugan Bans Brother Harem' on their search bars.
I'm not sure about the most popular ones specifically for Bakugan Bans Brother. But often, stories that involve unique character relationships, like how the brothers interact in unexpected ways in the Bakugan universe, tend to be popular. Maybe there are some where the brothers team up against a powerful enemy in a way that's different from the original series.
Some Bakugan - related forums might also be a good place to look for Bakugan Bans Brother fanfiction. Members of these forums may share their own works or recommend where to find such fanfiction. Additionally, you could check out Wattpad. It has a large collection of different types of fanfiction, and there's a chance you'll find the Bakugan Bans Brother fanfiction you're looking for there.
Create interesting plotlines. You can start with a simple premise like a portal opening between the two worlds and then build on it. Incorporate elements from both Naruto and Bakugan. Maybe there's a mission to find a lost Bakugan in the Naruto world. Also, don't forget about character development. As the story progresses, the main character and the harem members should grow and change. This could be in terms of their relationships, powers, or worldviews.
A third popular trope is the 'forbidden love' aspect. Maybe a relationship between a Naruto character and a Bakugan - related character is frowned upon in their respective worlds. This adds an element of drama and tension to the fanfiction. For example, if a shinobi from Naruto falls in love with a Bakugan trainer, their different cultures and duties might create obstacles for their relationship.
One good Jesse Glen and Oc Bakugan fanfiction could be about their adventures in a new Bakugan world. Maybe they discover a rare Bakugan and have to protect it from evil forces. Another could focus on their friendship growing stronger as they face challenges in Bakugan battles together.
One great Bakugan Wavern fanfic could be about her adventures in a new dimension. It might explore her powers in ways not shown in the original series.
One that comes to mind is 'Naruto in the World of Soul Eater'. It has an interesting plot where Naruto is somehow transported to the Soul Eater world and gets involved in a harem situation. The author does a great job of blending the two universes together.
One idea could be a female OC who has a special power that allows her to communicate with Bakugan on a deeper level. For example, she can understand their emotions and motives. Another idea is a female OC from a different dimension who enters the Bakugan world and has to adapt to its rules while also bringing in her own unique skills. She could be a healer in her own dimension but discovers she has combat abilities in the Bakugan world.
One interesting story could be about a female Bakugan trainer who discovers a rare Mechtanium Bakugan. She has to train it while facing challenges from other trainers who are jealous of her discovery. The story could focus on her journey of building a bond with the Bakugan and proving herself in battles.