You can start by looking on popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions across various fandoms, so there's a good chance you'll find some 'Justice League Watch Avengers' ones there.
Yes, there are plenty. You can check out websites like Archive of Our Own (AO3). There's a wide variety of fan - created stories that blend elements of the Justice League and Marvel universes. Some might focus on crossovers where characters from both meet, while others could be unique takes on the individual characters within the context of a combined universe.
Fanfiction.net is another option. It has been around for a long time and has a huge number of stories. Although the interface might not be as modern as some other sites, it still has a lot of great 'Justice League' and 'Marvel' related fanfiction. Just be prepared to do some sifting through the search results.
Maybe a story where some of the younger members of the Young Justice team are frustrated with the Justice League's methods and decide to take on a mission on their own, but end up getting in over their heads and have to call in the League for help. This could lead to a lot of character development and some interesting dynamics between the two groups.
One interesting fanfiction could be where the Justice League members are magically transported to the Avengers' universe and they have to team up to fight a common enemy. For example, they might face a powerful cosmic entity that neither group could defeat alone.
The story likely involves the Suicide Squad being tasked with taking on the Justice League. Maybe there are some sort of power struggles or misunderstandings that lead to this extreme situation where the anti - hero group is pitted against the heroes.
The plot could involve the Justice League facing off against Thanos. Maybe Superman tries to take on Thanos one - on - one at first, but realizes he needs the whole team. Batman could be strategizing on how to get the Infinity Stones away from Thanos. Wonder Woman could be leading the charge in the battle scenes, using her strength and skills. And Flash could be using his speed to either steal the stones or disrupt Thanos' attacks.
Well, in this fanfic, perhaps the Justice League has been poisoned or mind - controlled. Batman, being the resourceful hero he is, might first analyze the situation carefully. He could then track down the source of the problem, whether it's a new super - villain or an old enemy with a new trick. He'd likely use his Bat - computer to find a cure or counter - measure and then fight his way through any minions to administer it to the League members, saving them from certain doom.
Well, one possibility could be that Naruto somehow gets transported to the DC universe where the Immortal Justice League exists. Maybe he teams up with them to fight a common enemy like Darkseid or some other powerful villain. Naruto's unique jutsu and combat skills would add a new dynamic to the League's battles.
One idea could be that the female vampire OC is initially a foe. She might be causing chaos in the city, perhaps by preying on criminals at first but then getting out of control. The Justice League has to figure out how to stop her without killing her. They discover she has a tragic backstory that led her to become a vampire, and they try to rehabilitate her.