One idea could be a story where Jazz and Optimus Prime have to team up to face a new, powerful enemy that neither could defeat alone. Maybe this enemy has the ability to disrupt the Autobot's communication systems, and Jazz's skills in espionage and Optimus Prime's leadership are crucial in devising a new way to communicate and ultimately defeat the foe.
A good fanfiction could involve Jazz getting injured in a battle. Optimus Prime, who sees Jazz as a valuable and beloved comrade, takes it upon himself to protect and nurse Jazz back to health. During this time, they have deep conversations about their hopes for the future of Cybertron and their place in it, strengthening their bond.
Perhaps a fanfiction where a powerful artifact is discovered that has the potential to change the balance of power on Cybertron. Megatron wants it for his own gain, and Optimus Prime wants to protect it. But when they both touch it simultaneously, they are transported to an alternate dimension where they must work together to find a way back, all while learning more about each other than they ever thought possible.
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 Prime and Starscream are forced to team up during a crisis that threatens both Autobots and Decepticons. They start to see each other in a new light and develop an unlikely friendship. Another could be a story where Starscream is injured and Optimus Prime has to make the choice between helping him or leaving him to the mercy of other Decepticons. This could lead to a complex relationship between them. A third idea is a time - travel plot where they end up in an alternate universe where their roles are reversed and they have to figure out how to get back to their own universe while dealing with their changed relationship.
There could be a fanfiction where a strange energy source affects Optimus Prime and Megatron, causing them to swap personalities or abilities. This would be a humorous yet also thought - provoking plot. They would have to navigate their new selves while still trying to lead their factions. The Autobots would be confused by an aggressive Optimus and the Decepticons would be equally bewildered by a more pacifist Megatron.
Another plot could be set in a post - war scenario. The Autobots are rebuilding their world, and Optimus Prime and Arcee are tasked with different aspects of the reconstruction. However, they keep finding excuses to work together. As they do, they gradually fall in love while also dealing with the trauma of the war and the challenges of creating a new future for their kind.
In a more action - packed way, their relationship could be portrayed as a sort of 'yin and yang'. Jazz is quick and nimble, often taking risks that Optimus Prime might not initially approve of. But over time, Optimus realizes that Jazz's boldness is what the Autobots need sometimes. And Jazz learns to respect Optimus's more cautious approach. They balance each other out in battles and in decision - making, creating a unique dynamic.
A good storyline might involve the OC being from a different dimension. Optimus Prime discovers this when a strange energy signature leads him to the OC. They have to work together to figure out how to send the OC back to their own dimension while also dealing with the Decepticons who want to use the OC's dimension - hopping ability for their own evil plans.
Perhaps there's a story where Optimus and Megatron are both stranded on a desolate planet. Without their armies and with limited resources, they have to rely on each other to survive. As they struggle to find a way off the planet, they start to understand each other better. Megatron realizes that Optimus isn't just a naive idealist and Optimus sees that Megatron has reasons for his actions that are more complex than just pure evil.
One idea could be that Optimus Prime somehow ends up in the RWBY universe and teams up with Team RWBY to fight a common enemy. Maybe a new type of Grimm that is attracted to his Cybertronian energy.
One plot idea could be that Megatron and Optimus Prime are forced to team up in an alternate dimension. They have to put aside their differences to face a common enemy that is threatening the very fabric of that dimension. Maybe it's an ancient evil that has the power to destroy all Cybertronians.