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.
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 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 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.
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 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.
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 exploring a hidden planet during the Dark Voyage. The Maximals and Predacons could discover a new energy source there that changes the power dynamics. Maybe there are ancient Transformers on this planet with unique abilities.
One plot idea could be that Blackarachnia and Silverbolt are forced to team up on a mission in a dangerous part of the Beast Wars world. They initially clash due to their different personalities and allegiances but gradually come to understand and respect each other.
Perhaps they get transported to an alternate dimension where they have to rely on each other to survive. In this new place, they find out things about their pasts that they never knew before. Silverbolt might learn about Blackarachnia's reasons for being the way she is, and she might see that he is not just a naive goody - two - shoes. This could lead to a deeper understanding and a possible change in their relationship.