How about a crossover with a post - apocalyptic world? The Angels of Death duo would find themselves in a world full of ruins and scarce resources. They would have to deal with new threats like mutated creatures and other desperate survivors. Their relationship could be further tested in this harsh new environment.
Another plot could be a what - if scenario. What if Zack and Rachel escaped the building and had to live in the outside world? They would face new challenges like dealing with society's norms and trying to hide their past. It could show a different side of their relationship as they adapt to a new environment.
A Weeping Angels crossover with 'Star Trek' could be really cool. Imagine the Angels on a starship. The crew of the Enterprise would initially be baffled by the Angels' unique form of attack. They would have to use their advanced technology and knowledge of different species to find a way to keep from blinking and being sent back in time. Maybe they could develop a special device that emits a frequency that keeps the Angels frozen in place.
A crossover with 'Fullmetal Alchemist' could also be fascinating. Maybe Edward Elric discovers the Death Note in his search for the Philosopher's Stone. He would be conflicted because his moral code as an alchemist goes against using such a tool for killing, yet the power it offers could potentially help him achieve his goals in a different way.
One idea could be a crossover with the 'Mission: Impossible' series. The Angels could team up with Ethan Hunt's crew to take on a powerful international criminal organization. They could use their different skills, the Angels' charm and combat abilities along with the high - tech gadgets and espionage skills of the Mission: Impossible team.
A plot could also revolve around Harry going back in time to the origin of the Master of Death legend. He discovers secrets about how the power was first created and used. Along the way, he meets his ancestors or other powerful wizards from the past. This could change his understanding of his own power and his role in the wizarding world.
One idea could be a crossover between a classic superhero like Superman and a powerful anime character like Goku. Picture them in a battle where they have to adapt to each other's fighting styles. Another could be a crossover of characters from different horror universes, like Freddy Krueger and Pinhead, in a fight to the death in a nightmarish realm. And a third idea might be to cross a high - fantasy character like Gandalf with a modern - day action hero like John Wick. They could team up against a common enemy in a world that blends magic and modern weaponry.
Another possibility is a crossover with 'God of War'. Death and Kratos could meet. Given their both powerful and somewhat vengeful natures, they could either become bitter enemies or reluctant allies. The story could explore their different views on death, with Death being an embodiment of it and Kratos having a very personal and violent relationship with death in his own journey.
One idea could be an OC who is a half - angel, half - demon and is on a quest to find their true identity. They struggle between the good and evil tendencies within them.
One interesting Angels of Death fanfiction could be one that focuses on the backstories of the characters. For example, exploring more about Rachel's life before she entered the building. Maybe there's a fanfic where we see how she coped with her difficult family situation in more detail.
In some fanfictions, Dean might raise angels with a special purpose. Like he raises a group of angels to help him save Sam who has been trapped in a different dimension or something equally dire. The angels have their own motives and secrets, and as they work with Dean, all these secrets start to unfold, leading to a complex and engaging story.