One plot idea could be exploring Jack's relationship with his mother June in a more in - depth way during the Transformers chaos. Maybe he has to protect her from a new threat that the Autobots and Decepticons aren't aware of yet.
Another interesting plot could be a time - travel scenario. Jack and June somehow get sent back in time to the early days of the Transformers on Cybertron. They have to navigate this strange new world and find a way back home while also dealing with the political and social unrest on Cybertron at that time. This could involve Jack and June forming unexpected alliances with Cybertronians and learning more about the origin of the Transformers conflict. It would be a great way to expand on their characters and show how they adapt to a completely different environment.
Some specialized Transformers fanfiction forums might also be a great place to look. These forums are focused specifically on Transformers fan creations, including fanfictions. They might have a more curated selection or even some exclusive stories about Jack and June Darby. However, make sure to follow the rules of the forum when you're searching and reading.
One positive trait is her compassion. In fanfiction, she often shows great care for the Autobots, like when they are injured. She uses her medical skills selflessly. Another is her adaptability. She is able to handle the strange and dangerous situations that come with the Autobots being on Earth. For example, she quickly gets used to the idea of giant robots from outer space living among humans.
One possible plot could be that Jack's mutant powers allow him to better communicate with the Transformers on a mental level. This new ability helps the Autobots in their battles against the Decepticons as he can relay information faster and more accurately.
One idea could be that Jack discovers a hidden power within Arcee that she was not aware of herself. They then have to go on a quest to find out more about this power and how it can be used to help the Autobots in their fight against the Decepticons. Another plot could be that Jack gets lost in a dangerous part of Cybertron and Arcee has to brave all sorts of perils to find and rescue him.
Jack Darby is in love with Miko. But Miko has her eyes set on Bulkhead in a more than friendly way. Jack is always there for Miko, listening to her talk about Bulkhead's heroic deeds. He tries to hide his pain and be a good friend, but every time he sees them together, his heart aches.
Jack could travel to a time when the Autobots first arrived on Earth and help them understand human culture faster, thus forging stronger alliances earlier. This would change the whole dynamic of the war on Earth.
The OC could be from another planet that has a connection to Cybertron. Jack and the OC meet when she is looking for something on Earth related to her home planet. They start off as strangers but gradually fall in love as they discover more about each other's worlds.
One plot idea could be Jack and Miko getting lost in an uncharted part of Cybertron. They have to rely on each other's skills, Jack's strategic thinking and Miko's boldness, to find their way back. Another could be a situation where they accidentally switch bodies due to some alien technology malfunction. This would lead to humorous and also challenging situations as they try to adapt to each other's lives while in the wrong bodies.
Let's say Jack Darby has an unrequited love for a new Autobot that has joined the team. This Autobot is more focused on the war against the Decepticons. Jack tries to get closer to this Autobot by learning more about their technology and fighting skills. However, the Autobot remains oblivious to Jack's romantic intentions, leaving Jack to deal with his unrequited love in silence.
Yes, there are some out there. You can start by looking on fanfiction platforms like Archive of Our Own or FanFiction.net. Just search for 'Transformers x Jack Darby is a Mutant' and you'll likely find a variety of stories with different takes on this concept.