Well, perhaps in the fanfiction, Bumblebee gets taken by a time - traveling villain. This villain could take Bumblebee to a different era where he has to figure out how to get back while also facing new threats. Or he could be taken by a powerful wizard - like being in a fantasy - crossed - with - Transformers setting, and he has to break free from the magical spells.
One idea could be that Bumblebee is taken by a group of Decepticons who plan to reprogram him. Another could be that he's taken by a secret human organization for study. Maybe he's taken by a powerful alien race to use his abilities for their own purposes.
One idea could be that the bumblebee has a magical adventure in a garden full of talking flowers. The flowers need the bumblebee's help to save their home from an evil weed. Another could be that the bumblebee befriends a lonely little girl who can't go outside much, and they have heart - warming encounters through her window.
One idea could be that Baby Bumblebee gets lost during a battle and Arcee is the one who finds him. She then has to protect him while they try to find their way back to the Autobot base. Another could be a story where Arcee teaches Baby Bumblebee some important combat skills in a fun and unique way. Maybe she creates a sort of training course just for him.
A plot could involve Bumblebee getting damaged and losing his memory. The RWBY characters find him and try to repair him while also helping him regain his memories. As they do this, they learn about the Transformers universe and Bumblebee starts to adapt to the RWBY world, eventually using his unique abilities to help them in a big battle against a powerful Grimm horde and a new villain that has emerged.
A time - travel plot could also be interesting. They could be sent back in time to an era when Cybertron was in a different state. There, they might meet younger versions of themselves or other important Transformers. This could change their perspective on their own history and relationship, and they might come back to the present with a new outlook on their rivalry.
In some fanfictions, it could be an unknown alien species. They might have detected Bumblebee's unique energy signature and decided to take him to study his technology or abilities. This could lead to all sorts of interesting adventures as Bumblebee tries to communicate with them and find a way to escape.
Maybe a fanfiction where Dark Energon is being used to power a new super - weapon, and Bumblebee has to infiltrate the Decepticon base to stop it. Along the way, he discovers some secrets about the origin of Dark Energon and its connection to the Transformers' past. This would be an exciting plot full of mystery and adventure.
One plot idea could be that Bumblebee and Arcee have to team up to protect a powerful artifact from the Decepticons. They start off not getting along well due to their different fighting styles, but as they face challenges together, they learn to respect each other and become a great team.
One plot idea could be that Bumblebee and Blitzwing are forced to team up during a crisis on Earth. They start off not trusting each other at all. Bumblebee is suspicious of Blitzwing's motives as he's a Decepticon. But as they face challenges together, they gradually learn to understand each other's strengths and weaknesses. For example, Blitzwing's triple - changer ability proves useful in getting them out of tight spots, and Bumblebee's speed and agility help in evading enemies. Another idea is a story where Bumblebee has to convince Blitzwing to defect from the Decepticons. This could involve Bumblebee showing Blitzwing the positive aspects of Autobot life, like friendship and protecting the innocent.
A really interesting plot could be set in an alternate universe where Bumblebee and Optimus Prime are not part of the Autobot - Decepticon war. Instead, they are explorers. They could encounter a strange new planet or a powerful ancient artifact that tests their relationship and their understanding of each other. This would be a great opportunity to explore their characters outside of the typical war - torn setting.
One plot idea could be that Optimus and Bumblebee are on a mission together in a strange new world. There, they face a series of challenges that test their bond. They rely on each other more than ever, and through their shared experiences, their relationship deepens in a non - romantic but very strong friendship way. Maybe they discover a new power source that only they can unlock together.