One idea could be an angel family dealing with a new threat from a powerful dark entity. The angels have to put aside their internal differences to protect the world. For example, an angel family that has a young and inexperienced angel who discovers a unique power that could be the key to victory but they need to train the young one fast.
Perhaps a story about an angel family that gets exiled from heaven and has to learn to live among humans. They face many challenges like hiding their true nature and dealing with human emotions which are completely new to them. They could also encounter other supernatural beings on earth who either help or hinder them in their new life.
A good plot could be an angel family being split apart due to a curse. Each member is sent to different dimensions. The story then follows their individual journeys as they try to find a way back to each other and break the curse. Along the way, they learn more about themselves and the true meaning of family, all while facing various challenges in the strange dimensions they are trapped in.
One idea could be that the bat family encounters a supernatural force that gives them new powers. For example, they might come across a magical amulet that allows them to fly without their gadgets for a short time.
One plot idea could be that the reader, an angel, is sent on a mission to redeem Lucifer. Along the way, they have many intense philosophical debates about good and evil, which gradually lead to an unexpected bond between them.
One idea could be to explore the backstory of the angel. Maybe they were once a high - ranking celestial being who fell from grace but still holds on to their sense of justice, which is why they carry the shotgun. Another idea is to have the angel team up with a human hunter in the supernatural world, and they face off against demons that are causing chaos in a small town.
A possible plot could be Sam's relationship with Dean in this new form. Dean might be initially skeptical or even a bit scared of Sam's transformation. Sam could then try to convince Dean that he's still the same person on the inside. Also, Sam could be on a mission given to him by a higher - up angel. But he starts to question the motives of the angelic hierarchy as he realizes some of their actions might not be as noble as they seem. He could then use his new powers to try and change things from the inside.
A great plot for a Clockwork Angel fanfiction could be a time - travel story. Tessa or one of the other characters could accidentally travel back in time to a crucial moment in Shadowhunter history. They would then have to navigate this new - old world without changing the course of history too much. Another idea is to focus on the love triangle between Tessa, Will, and Jem from a different perspective. Maybe from the point of view of a bystander who can see things the main characters can't. And a fanfiction that dives deeper into the world of the automatons and how they were created and what their ultimate purpose might be could also be really engaging.
You could write a fanfiction where the Angel Blade has a mind of its own. It communicates with the wielder in a mysterious way, guiding them towards a greater purpose. The story could then revolve around the wielder trying to understand the blade's intentions, while also dealing with external conflicts like battles against dark forces and political intrigue within their own group.
One idea could be a crossover with a detective show. The angels could assist the detective in solving a case that has a supernatural element to it. For example, they might help the detective figure out that a series of murders are being committed by a demon in human form.
One idea could be Percy facing a new chaos - themed villain who can manipulate time in a disorderly way. Percy has to find a way to break the time - loops the villain creates.
One idea could be that a fallen angel joins the Avengers with a mysterious power that can either save or doom the team. For example, the fallen angel might have the power to manipulate time on a small scale, which could be useful in battles but also dangerous if misused.
Maybe the angel on the shoulder has lost its memory and as the story progresses in the fanfiction, the protagonist helps the angel regain its memories while also dealing with their own problems in the human world, like school or relationship issues.