I'm not sure of a specific one off the top of my head, but you can try searching on fanfiction.net. There are likely many great stories there with that premise.
A fanfiction could explore the emotional turmoil the Avengers go through while watching the Civil War trailer. For example, Wanda Maximoff might see the trailer and be afraid of the power she wields and how it's being portrayed as a threat. Vision, on the other hand, tries to analyze the trailer from a logical perspective, but also feels a sense of unease. The team realizes that the trailer is not just a promotional piece but a warning of what could come if they don't sort out their issues soon.
Well, Naruto's powerful jutsu could completely change the dynamics. His shadow clone technique could be used for various strategies. He might side with Captain America as he values friendship and loyalty, just like Naruto values his comrades in Konoha. And his Rasengan could be a very powerful weapon against the opposing side.
In some fanfictions, the Avengers might be shocked. They could see the looming threat in the trailer and start to strategize right away. For example, Tony Stark might start making sarcastic remarks while also thinking about how to upgrade his suit to face the new challenges.
You can try platforms like YouTube. Sometimes fans create and post fanfiction - inspired videos related to the Avengers Infinity War trailer on there. However, make sure to abide by the platform's terms and conditions.
Naruto's powers could be a game - changer. His ability to create thousands of shadow clones means he could overwhelm the opponents. In a battle - field like the Avengers Civil War, this would be a huge advantage. His Rasengan, a concentrated ball of chakra, could break through strong defenses of the super - powered beings.
There's a fanfiction called 'Young Spidey in Civil War'. It's really good because it explores Spiderman as a young and inexperienced hero in the complex situation of the Civil War. It shows his growth and how he tries to navigate the difficult political and moral landscape of the war between the Avengers.
One common plotline is the Avengers reacting to alternate versions of the Civil War events. For example, they might see a version where more heroes died during the battle. Another is them getting to interact with the characters from the Civil War in a different setting, like a post - apocalyptic world where the events of Civil War led to total chaos.
In 'Avengers watch Civil War' fanfics, the theme of understanding is quite prominent. The Avengers come to understand the motives and reasons behind the actions of their fellow members during Civil War. Another common theme is regret. They regret the way things turned out and how it affected their relationships. This regret often leads to them trying to make amends. Additionally, the theme of growth is present. They grow as individuals and as a team by learning from what they see when they watch the Civil War events.
In fanfiction, some Avengers might be shocked. For example, Thor could be angry seeing Thanos' looming threat more clearly in the trailer. He might vow to stop him immediately.