For comical fanfiction, they would probably have a good laugh. Reading about themselves in silly situations, like getting their powers mixed up in a ridiculous way or having a misadventure in a grocery store, would be a light - hearted break from their serious superhero duties.
If they read action - packed fanfiction, they might be excited. They could see themselves in epic battles and cool scenarios that they hadn't thought of before. For example, a fanfiction where they take on an intergalactic threat in a way that's more intense than their normal missions would probably get them pumped up.
Romance - centered fanfiction might make them a bit uncomfortable at first. Imagine a character reading about a romantic relationship between themselves and another teammate that they've never considered in that way. But on the other hand, it could also make them think about their relationships in a new light, perhaps leading to deeper friendships or a better understanding of their feelings towards others.
Some of them might be amused. They could find the different takes on their characters and stories quite entertaining. For example, Superman might chuckle at a fanfic that has him in a comical situation.
Dick would probably be excited. He loves the idea of fans being so engaged with their world and would enjoy reading the different takes on their relationships. He might even leave positive comments if he could.
The Flash would likely find it really entertaining. He might enjoy reading about his super - speed being used in all sorts of crazy ways in the fanfiction. And he could also use it as a way to pass the time when he's not out saving the day. He might even start to wonder if some of the ideas in the fanfiction could actually work in real - life superhero situations.
They might be intrigued. The different takes on the MCU heroes and villains could capture their attention.
Some members of Young Justice could be embarrassed. For instance, if there are romantic fanfictions about them that are a bit too cheesy or if their weaknesses are overly emphasized in a not - so - flattering way. But others might be really intrigued and want to explore more of what the fans think about them.
Batman would probably be more critical. He'd analyze how the fanfiction portrays his detective skills and his relationship with the other members of the Justice League. He might not like it if the stories make him seem too soft or too brutal, as he has a very specific self - image.
Some might be amused, while others could be offended. It depends on how they are depicted in the fanfiction.
Some might be shocked. For instance, Batman is often portrayed in very different ways in fanfiction compared to his 'canon' self. Superman might raise an eyebrow at a fanfic where Batman is overly emotional. Others like the Flash might be really into it, finding the different takes on Batman's character and his adventures exciting.
Yang would likely have a big reaction. If the fanfiction shows her in a cool fight scene, she'd be all for it and might even show it off to her friends. But if it portrays her in a negative or weak way, she'd be really annoyed.
Some characters might be flattered. If they are depicted as heroes in the fanfiction, it would boost their egos. For instance, Oliver Queen might enjoy reading about himself as an even greater hero than he already is.