One great Supernatural and Avengers fanfiction is 'Avengers in the World of Supernatural'. It combines the two universes really well. The characters from both shows interact in a very interesting way, like Dean Winchester and Tony Stark having a sort of 'tech vs. old - school' banter.
Supernatural's power system is based on things like magic spells, holy water, and special weapons. The Avengers have powers like super strength, flight, and high - tech gadgets. In fanfiction that combines them, writers often have to find a way to balance these different power systems. Some fanfics might have the Avengers learning about the Supernatural power sources, while others might have the Supernatural characters being awed by the Avengers' powers. It creates a really interesting dynamic that sets the two universes apart in the context of fanfiction.
If the Avengers watched Supernatural fanfiction, there would be a lot of different reactions. Natasha might analyze the characters' motives and actions from a spy's perspective. Clint could be making sarcastic comments throughout. Bruce might be a bit worried about some of the more out - there plot elements and how they could potentially be real in a strange universe.
Sure, there are such fanfictions. These crossovers often play on the strengths of both universes. For example, Thor's knowledge of other realms could be useful in a hunt with the Winchesters. And the Avengers' teamwork could be put to the test against the spooky and powerful entities from Supernatural. It's a great way for fans to explore different combinations of their favorite characters.
Another great crossover could be Dean Winchester and Captain America. Dean is a tough hunter, used to fighting all kinds of monsters. Captain America is a symbol of justice and heroism. If they meet, they could exchange their combat skills and values. Maybe Dean could teach Cap some of his street - smart fighting techniques, and Cap could inspire Dean with his selfless and patriotic spirit.
One interesting crossover could be a story where the Avengers are facing a threat that has a supernatural origin, and they seek the help of the TFW. Maybe the Avengers are dealing with a horde of demons that they can't defeat with their usual technology and powers, and Sam, Dean, and Castiel come to the rescue with their knowledge of the supernatural world.
I think an alliance between Thor and the Winchester brothers would be very powerful. Thor has his mighty hammer and godly powers. The Winchester brothers have years of experience in hunting demons and other supernatural beings. Together, they could take on any enemy. They could use Thor's strength to directly confront powerful foes, while the Winchesters' knowledge of the supernatural would help them come up with strategies to defeat their enemies more effectively.
One idea could be that the Avengers are facing a supernatural threat that they can't understand. So they seek the help of the Winchesters from Supernatural. The Winchesters introduce them to the world of the supernatural, like demons and ghosts. And together they combine their skills, the Avengers' superpowers and the Winchesters' hunting knowledge to defeat the threat.
Fanfiction.net is also a good place. There are a lot of fan-written stories there. However, the search might be a bit more tricky. You may need to use specific tags related to Supernatural TFW and Avengers. For example, tags like 'Sam Winchester', 'Dean Winchester', 'Castiel' from Supernatural and 'Iron Man', 'Captain America' etc. from Avengers to narrow down the search.
Definitely Tony Stark and Dean Winchester. Tony with his high - tech gadgets and smart - aleck attitude, and Dean with his love for classic cars and no - nonsense approach. They would have some really interesting banter, and Tony could probably learn a thing or two about survival from Dean, while Dean might be impressed with Tony's technology.