Power and its consequences is also a prevalent theme. The Predacon OC might have unique and powerful abilities. But these powers can attract unwanted attention from both good and bad forces. This can lead to a series of events where the OC has to decide how to use their power responsibly and deal with those who want to use it for their own gain.
One great source could be Archive of Our Own (AO3). There are numerous Predacon OC fanfictions there. You can search for 'Transformers Prime Predacon OC' and sort by popularity or kudos. Some fanfictions might focus on a Predacon OC's journey within the existing storylines of Transformers Prime, like their interactions with the main characters or how they affect the overall plot.
The theme of redemption also appears often. If the male OC is a Decepticon or has done something wrong in the past, the story might focus on his journey to make amends. He could be trying to atone for his actions by helping the Autobots in their fight against the Decepticons. This can add a lot of depth to the character as he struggles with his past and tries to become a better 'bot or person in the Transformers Prime world.
Another theme could be acceptance. The OC, being an outsider as a homeless character, might struggle to be accepted by either the Autobots or other human characters. They may face discrimination or suspicion at first, but then gradually earn trust through their actions. This theme can add a lot of depth to the story as it explores relationships and character growth. It can also show how different characters in the Transformers Prime universe react to those who are different or in a less fortunate situation.
One common theme is the human OC's journey of self - discovery while being involved with the Autobots and Decepticons. Another is the relationship between the human OC and the Transformers, whether it's a friendship or a more complex bond. And often, there's the theme of the human OC helping to save the day in some way in the battles between the two factions.
One common theme is self - discovery. The male OC often has to figure out his place within the Autobot group and what makes him unique. For example, he might discover a new ability that sets him apart.
One common theme is self - discovery. The male autobot ocs often start out not fully knowing their capabilities or place in the team and then go through a journey to discover themselves. Another theme is friendship. They form bonds with other autobots, which helps them in their adventures. And heroism is also a theme, as they usually end up saving the day in some way.
A common theme is the relationship between the OC and Ratchet evolving from a simple acquaintance to a deep emotional bond. Another is the OC helping Ratchet deal with the stress of the war against the Decepticons.
A third common theme is the exploration of Knockout's character. The OC can act as a catalyst to show different sides of Knockout. Maybe the OC is kind - hearted and through their interactions, Knockout shows a more vulnerable or less - evil side than what we usually see in the show. This kind of character exploration through the relationship with the OC is quite popular in such fanfictions.
Give your OC Predacon a backstory. Maybe they were raised in a different environment than other Predacons. If they were found and raised by an Autobot, for instance, it would greatly influence their view of the world. This backstory can explain their motives and actions in the fanfiction. Also, consider their relationships with other characters. Do they have a rival within the Predacon clan? Or a special bond with a particular Transformer? These relationships can add depth to the character.
One idea could be to create an OC Predacon who is an outcast in their own clan. They might have different beliefs or abilities that set them apart. For example, this OC could have the power to communicate with other species in a way that other Predacons can't. This would lead to a lot of internal conflict within the clan as well as interesting interactions with other Transformers.