One possible fanfiction could be about Optimus Prime and Megatron having to team up against a greater threat. Maybe an ancient evil from Cybertron's past resurfaces that is so powerful that their usual enmity has to be put aside. They start off distrusting each other but as they face battles together, they gradually come to respect the other's fighting skills.
One possible fanfiction could be about Blitzwing and Bumblebee being forced to team up during a Decepticon attack on an Autobot base. Blitzwing, with his three personalities, could create some interesting and comical situations as he tries to work with Bumblebee. Maybe at first they don't trust each other, but as the battle progresses, they start to respect one another's skills.
One possible fanfiction could be about Bumblebee stumbling upon a cache of Dark Energon. Maybe he initially doesn't realize the danger it poses. He could be curious and start investigating it, which then leads to some strange effects on him, like his systems glitching in new and unexpected ways. This could put him in a precarious situation where his Autobot friends have to figure out how to reverse the effects before it's too late.
The road map could include starting with the original animated series and movies, then moving on to the various comic book series and novelizations. It's all about exploring the different media to get a full picture.
Well, it would be very strange considering Starscream is male. But if such a fanfiction were to exist, it might involve some sort of alien or magical transformation that enables him to carry a spark or something equivalent to a pregnancy. It could explore how other Transformers react to this unexpected situation, and how Starscream himself copes with the physical and emotional changes.
There was an Autobot male OC, named Steel. Steel was not your typical Autobot. He was smaller in size compared to others but had a heart full of courage. He was an expert in fixing damaged Autobots. In a major battle, many Autobots were severely injured. Steel worked tirelessly to repair them. He faced challenges as the Decepticons were constantly trying to stop him. But with his quick thinking and determination, he managed to keep his comrades in fighting shape, earning the respect of all Autobots in the process.
One possible fanfiction could be about Sam's baby sister being born with a special connection to the Transformers. Maybe she can communicate with them telepathically. This could lead to all sorts of adventures where she helps the Autobots in ways that Sam couldn't. For example, she might be able to sense when the Decepticons are planning a surprise attack and warn the Autobots in time.
In this fanfiction, it could explore how their friends from the Autobot side react. The Autobots might offer their protection and support. For example, Bumblebee could be like an over - protective big brother figure. And Mikaela might have to deal with the physical and emotional changes of pregnancy while also being part of the action - filled Transformers world.
First, know the characters well from both universes. For Steven Universe, understand the powers and personalities of the Crystal Gems and Steven. For Transformers, know the Autobots and Decepticons. Then, find a good starting point for the crossover, like an unexpected encounter. Don't forget to keep the tone consistent with both franchises.
It could be really cool. Imagine Steven's gem powers interacting with the Transformers' technology. Maybe the Crystal Gems could help the Autobots in some way, like using their powers to repair damaged parts. Or the Transformers could introduce new ways of using energy to the Gems.