For a Star Wars Rebels and Mandalorian OC in fanfiction, you could start with a unique backstory. Maybe your OC is a Mandalorian who was orphaned during the Clone Wars and grew up on a planet in the Outer Rim. They could have a special skill like being an expert in hand - to - hand combat with a Mandalorian vibro - blade. Their armor could be a unique blend of traditional Mandalorian design and scavenged parts from old Separatist droids, giving it a distinct look. This OC could then cross paths with the crew of the Ghost in Star Wars Rebels, leading to all sorts of adventures.
An interesting plot could be an OC who is a mechanic with a mysterious past. They join the Rebels and start to tinker with their ships and weapons, but they also have a connection to an ancient Jedi artifact. As they work with the Rebels, they gradually uncover the secrets of the artifact and how it can be used against the Empire. Or perhaps an OC who is a youngling that was hidden away during Order 66 and now, years later, emerges to join the Rebels and seek revenge on the Empire while also learning the ways of the Force from the few remaining Jedi.
An original character (OC) in the Star Wars Rebels universe as an Inquisitor can be really exciting. First, think about their backstory. Maybe they were a former Jedi who fell to the dark side out of a desire for power or revenge. For appearance, they could have a distinct look, like a long, black cloak with red accents. Their lightsaber could be unique, perhaps with a curved hilt.
First, consider their backstory. For example, if they grew up on a planet occupied by the Empire, they might have a deep - seated hatred for the Imperials. Their appearance should also fit the Star Wars universe. Maybe they have unique markings or clothing styles from their home planet. Their skills and abilities should be relevant to the story. If they're a fighter, they need combat skills, but if they're a spy, they need stealth and intelligence - gathering skills.
Some Star Wars Rebels time travel fanfics focus on the relationships between the characters. When time travel is involved, characters may interact with their past or future selves. This can lead to some really interesting character development, like Kanan having to come to terms with a future version of Ezra who has changed a great deal due to his time - traveling experiences.
One great Sabine and Ezra fanfic could be one where they go on a secret mission together. It might explore their growing bond as they face challenges. Maybe they have to infiltrate an Imperial base, and along the way, they learn more about each other's pasts. Their different skills, Sabine's artistry and combat skills and Ezra's connection to the Force, would make for an interesting dynamic during the mission.
Well, Galen Marek in a Star Wars Rebels fanfic might be a bit of an anachronism at first glance. But if you think about it, the Star Wars universe is vast. He could have been in hiding for years. In the context of Rebels, he could be a force for change. He might be drawn to the Rebellion's cause because of his own experiences with the Empire's cruelty. His presence could also attract unwanted attention from the Empire, leading to some tense moments in the fanfic. For example, the Inquisitors might sense his power and start hunting him, which could then put the Rebels in danger as they try to protect him.
One great Ezra and Sabine fanfic is 'Bonding on Lothal'. It really delves into their relationship during the Rebellion on Lothal. The author does an amazing job of showing how they rely on each other and grow together as characters.
One similar fanfic could be 'Endless Struggles in the Rebellion'. It also focuses on the hardships that the Star Wars Rebels characters face. Another might be 'Troubled Times for the Ghost Crew' which, like the one you mentioned, likely has the crew dealing with one problem after another. There's also 'Perils of the Rebellion' which would probably have a similar theme of the rebels constantly facing difficulties.
One aspect could be the Rebels' reactions to the complex political situations in the Clone Wars. They might be shocked or inspired by the different alliances and betrayals that took place. It could also show how the Clone Wars era influenced the technology and weaponry available during the Rebels' time, like how the Rebels might see the evolution of starfighters from the Clone Wars to their era.