One possible fanfiction could be about Wakiya and Shu forming an unexpected alliance. They might start off as rivals but then find common ground in their love for beyblade. For example, they could team up to face a stronger opponent that neither could defeat alone. This would involve them learning to trust each other and combining their unique skills.
The plot could be a time - travel adventure. Wakiya and Shu are sent back in time to the early days of beyblade. They have to work together to find a way back to their own time while also influencing the development of beyblade in the past. This would be filled with interesting encounters with the old - school bladers and a lot of action as they try to preserve the future of beyblade.
Good fanfiction would also explore their relationship in depth. It could show how they grow and change because of each other. For instance, Wakiya might become more humble because of Rantaro's influence, and Rantaro could become more ambitious in his beyblade skills thanks to Wakiya's drive. This kind of character development within the relationship makes for a great fanfiction.
One idea could be a story where Valt and Shu are training together for an upcoming big tournament. They face various challenges during their training, like dealing with new and powerful opponents' techniques. As they train side by side, they start to understand each other's strengths and weaknesses better, and their friendship deepens into something more, with a lot of cute and competitive moments along the way.
Another idea is that the fanfiction could focus on a time - travel or alternate universe scenario. Wakiya and Rantaro could find themselves in a different world where the rules of beyblade are completely different. They would have to rely on each other to figure out how to get back to their own world while also facing new and strange opponents.
Maybe Valt loses his memory after a particularly intense Beyblade battle. Shu then has to work hard to help Valt remember their friendship and their shared experiences in the Beyblade world. This could lead to a whole new dynamic in their relationship as Shu is desperate to bring back the old Valt.
A prevalent theme is also the idea of redemption. In some fanfictions, if Shu has gone through some tough times or made mistakes, Valt is often the one to bring him back, and this journey of redemption is intertwined with their relationship development. Also, there are fanfictions that focus on the power of their bond. How their connection gives them an extra boost in their Beyblade battles, not just physically but also mentally, and this bond then blossoms into a romantic relationship.
In a fanfiction, Valt and Fem Shu could be in a situation where they have to rescue their Beyblades from an evil force. Valt would be all ready to charge in head - first, while Fem Shu would be thinking of a strategic plan. Their different personalities would create some interesting dynamics as they work together to save their beloved Beyblades and in the process, become closer friends.
In a fanfiction, Female Shu could be a new transfer student to Valt's school. Valt, being the friendly and enthusiastic beyblader he is, welcomes her. They quickly discover their shared love for beyblading. However, Female Shu has a secret technique she's been developing. Valt, intrigued, tries to learn from her and in the process, they develop a bond that goes beyond just beyblading. They support each other through personal and beyblade - related challenges.
I'm not sure if there's a very specific 'Beyblade Burst Shu sneeze' fanfic out there. However, it could be an interesting concept. Maybe in this fanfic, Shu could be in the middle of a big beyblade battle and suddenly sneeze, which throws off his concentration and causes an unexpected turn in the match.