In this fanfiction, perhaps the Avengers are watching the trailer together in the Avengers compound. They might start arguing about whether the events in the trailer are going to be good or bad for their world. Some could be excited to see old foes return, thinking it's a chance to set things right, while others might be worried about the chaos it could bring to the already fragile multiverse. For example, Iron Man could be analyzing the technology shown in the trailer, trying to figure out if it's something they can use or need to defend against.
It could be Iron Man. Since he was always the brains behind a lot of the Avengers' tech and strategies, he might be the one analyzing every detail in the trailer and coming up with plans.
There's a fanfiction where the Avengers watch the trailer and then start making bets on what will actually happen in the movie. It's a really fun take on it. The banter between the characters is great, especially between Sam and Bucky. It's called 'Trailer Predictions: Avengers Edition' and can be found on Archive of Our Own.
One interesting plotline could be the Avengers having to deal with alternate versions of themselves that are brought into their universe during the events of No Way Home. It could lead to some really cool team - up and fight scenes.
Imagine the Avengers reading 'No Way Home' fanfiction. Loki would probably find it amusing and start plotting his own fanfiction - like twists in his head. Wanda Maximoff might be a bit emotional about it, relating to the characters' feelings in the story. Vision, on the other hand, would be trying to understand the concept of fanfiction itself and then make logical deductions about the Avengers' reactions based on their personalities.
Well, if the Avengers are watching 'Spider - Man: No Way Home' fanfiction, they might be looking for inspiration. Maybe they want to learn from the different scenarios presented in the fanfiction to better prepare for future threats in their own world. They could also be amused by the wild ideas and crossovers that often appear in fanfiction.
Some might be amazed. For example, Hawkeye would be impressed by Iron Man's new flying maneuvers. Others like Falcon could be taking mental notes on Iron Man's technology for his own gear. And Tony Stark himself would probably be enjoying the attention and bragging a bit about his new suit's features.
Some of them might be really amused. For example, Thor would probably laugh heartily at any creative interpretations of his character. He might say 'This Midgardian has a wild imagination!'.
There's a fanfiction where the Avengers watch 'No Way Home' and it really focuses on how Doctor Strange's actions in the movie inspire Wanda Maximoff to further explore her powers. She sees how Strange manipulates the multiverse and starts to think about how she could do something similar with her chaos magic. It's a great read for seeing Wanda's character grow in new ways.
A really interesting fanfiction could be where the Avengers view the events of 'No Way Home' from a different dimension. They see Peter's struggles and decide to intervene in a more creative way. Maybe they use their connections across the multiverse to find a solution that doesn't involve as much danger for Peter. Some fanfictions also explore the emotional reactions of the Avengers to seeing Peter go through so much in this movie.