Perhaps in the fanfiction, Megatron accidentally travels back in time to a pre - Beast Wars era on Cybertron. He then tries to change history to ensure his future victory. But his actions have unforeseen consequences that start to affect the present - day Beast Wars. The Maximals notice the changes in the timeline and follow Megatron back in time. This could lead to an epic battle in the past with the fate of both the past and present at stake.
One interesting plot could be Beast Wars Megatron getting his hands on a powerful ancient artifact on Earth that gives him an edge over the Maximals. This could lead to a series of battles where the Maximals have to figure out how to counter this new power. Another idea is a fanfiction where Megatron forms an unlikely alliance with a small group of Maximals to face a greater threat from a third, previously unknown faction. This would be full of tension as they try to work together while still being enemies at heart.
One idea could be exploring Blackarachnia's past before the Beast Wars. Maybe she had a different life or purpose that got derailed. Another could be a story where she forms an unlikely alliance with one of the Maximals, like Cheetor, and they have to work together to overcome a common threat. Or perhaps a fanfic that delves into her relationship with other Predacons, like how she might be trying to gain more power within their ranks while also dealing with her own internal conflicts.
One idea could be a human mechanic who discovers Megatron in a damaged state and tries to repair him while hiding him from other humans and Autobots. This could lead to a complex relationship where Megatron starts to question his views on humans.
One idea could be exploring how the other Transformers react to Megatron in this unexpected state. Maybe some are shocked, while others see it as a chance for a new beginning in the ongoing conflict.
Perhaps a story set during the Clone Wars where the Republic discovers a way to control the Zillo Beast and uses it as a weapon against the Separatists. But things go awry when the Beast breaks free from its control and starts wreaking havoc on both sides of the war, forcing the Jedi and the clones to find a new solution to stop it.
One idea could be a crossover where the characters from Transformers Prime end up in the Beast Wars universe. They could form alliances with the Beast Wars characters to fight a common enemy like the Predacons. Another idea is to explore the origin stories of some of the Beast Wars characters within the context of the Transformers Prime lore. Maybe there's a hidden connection between a Prime character and a Beast Wars character that could be uncovered.
Perhaps Vergil is from a parallel dimension where the Devil May Cry world and the Transformers Beast Wars world are already intertwined. He comes to the Beast Wars universe to seek a powerful artifact that could help him in his own dimension's battles. Along the way, he forms unexpected alliances with both Autobots and Maximals, and his presence changes the course of the Beast Wars as the different factions either see him as a threat or an opportunity.
Tarantulas is an interesting character to include. He has his own devious plans that often intersect with Megatron's, sometimes as an ally and sometimes as a rival. Tigatron, with his connection to nature and his more spiritual side, can bring a different perspective to the story. And Waspinator, for his comical yet tenacious nature. Despite being often defeated, he always comes back, and his interactions with Megatron can be both humorous and revealing of Megatron's character.
One idea could be creating an OC that is a hybrid of two different Beast Wars species. For example, a half - Maximal, half - Predacon. This OC could struggle with identity issues as they don't fully belong to either side. Another idea is an OC with a unique power, like the ability to control plants in the Beast Wars world. This could add an interesting dynamic as they interact with the other characters and the environment.
One idea could be a crossover with the Transformers Prime series. Imagine the Beast Wars characters interacting with the more modern Transformers designs and storylines from Prime. It could lead to some really cool battles and character development as they learn from each other's different ways of dealing with the Autobot - Decepticon conflict.
One idea could be exploring the backstories of the less - known characters in more depth. For example, delving into the origin of a minor beast warrior and how they came to be involved in the war.