Flash x Arrow fanfiction contributes by expanding the DC universe in the minds of fans. It allows for different interpretations of the characters. For example, a fanfiction might show Flash with a different personality trait that we haven't seen in the official comics or shows. This gives fans a chance to explore new aspects of their favorite characters.
Well, the origin of The Flash, specifically Barry Allen, is quite interesting. He was just an ordinary guy, a smart forensic scientist. But a freak accident changed his life forever. That lightning strike in the lab full of chemicals was like a catalyst. It not only gave him the ability to move at incredible speeds but also enhanced his reflexes and thinking speed. And with great power came great responsibility. So, he took on the mantle of The Flash to keep his city safe from villains who would take advantage of the chaos.
Another great one is 'Watchmen' by Alan Moore. It's not just a superhero story but a deconstruction of the genre. The characters are morally ambiguous, and the complex narrative and detailed art make it a must - read. It also has a lot of political and social commentary.
I think Spider - Man from Marvel has an amazing story. Peter Parker is just an ordinary kid who gets superpowers by accident. He has to juggle his normal life, including school and relationships, with his new responsibilities as a superhero. His struggles are very relatable. He faces financial problems, has to keep his identity a secret, and still tries to do the right thing. It's a story that shows that with great power comes great responsibility.