Fanfic about Captain America in the Justice League: What are some interesting plot ideas?

Perhaps in the fanfiction, a cosmic event causes a rift between the Marvel and DC universes. Captain America and the Justice League find themselves on the same side as they are the only ones who can prevent the destruction of both universes. They must overcome their differences in ideology and power - sets. Captain America's sense of justice and the Justice League's diverse powers and abilities would make for an interesting dynamic as they work together to close the rift and defeat the forces trying to destroy the universes.

In a fanfic, Captain America could fit into the Justice League by being the voice of the common man. The Justice League often deals with big, cosmic threats, but Captain America would remind them of the importance of protecting the ordinary people on the ground. His experience in World War II gives him a unique perspective on the cost of war and the value of peace, which could influence the Justice League's decisions when it comes to using force and resolving conflicts.

One interesting plot idea could be that Captain America and Agent 13 are on a mission to retrieve a powerful and dangerous artifact. Along the way, they face many challenges and have to rely on each other's skills. Agent 13 uses her espionage skills to gather intel, while Captain America uses his combat abilities to fight off enemies.

It could be really interesting. Steve Rogers' sense of justice and leadership would blend well with the Justice League. His military tactics could help in planning battles against powerful villains. For example, in a fight against Darkseid, Steve might come up with a strategy to use the different powers of the League members effectively, like having Flash create distractions while Superman goes for a direct attack.

One idea could be a story where Batman has to lead the Justice League in a fight against a powerful new villain who can manipulate time. This would put Batman's strategic skills to the ultimate test as he tries to coordinate the different powers of the League members. Another plot could be that a member of the Justice League is secretly under mind control and Batman has to figure out who it is before they cause too much damage.

One idea could be an OC with the power to manipulate time joining the Justice League. They could accidentally create a time rift during a battle, and the League has to fix it while also dealing with the OC's insecurities about their powers.

One idea could be that the Young Justice team has to prove themselves to the Justice League during a major alien invasion. The League initially doubts their abilities but as the battle progresses, they see the unique skills and teamwork of the young heroes.

One plot idea could be that Captain America and Scarlet Witch team up to face a new, powerful villain who has the ability to manipulate time. They have to combine Captain America's combat skills and leadership with Scarlet Witch's reality - warping powers to defeat the foe.

One plot idea could be that after being brainwashed, Captain America is made to believe his old friends are enemies. So he starts targeting the Avengers. Another could be that he is brainwashed to carry out a secret mission that goes against his moral code, like stealing important artifacts for a shadowy organization. And he has to struggle to break free from the brainwashing when he starts to have flashes of his true self.

One idea could be exploring the backstories of the lesser - known members in more detail. For example, Martian Manhunter's life on Mars before coming to Earth.