1. Anne Hathaway (Black Cat)
Anne Hathaway was rumored to play Black Cat for Spider-Man 4 however when the movie was cancelled so was the role.
2. Josh Hutcherson (Spider-Man)
Josh Hutcherson was a finalist for the Amazing Spider-Man 2012 reboot, it was rumored that it was down to Hutcherson and Andrew Garfield. Apparently there is a stunt tape of Hutcherson as Spider-Man.
3. John Krasinski (Captain America)
When Chris Evans originally said "no" to playing Cap, John Krasinski became the front-runner and screen tested twice for the role. However when Chris Evans changed his mind he got the part and no audition was required!
4. Tom Cruise (Tony Stark/Iron Man)
start and Marvel's Kevin Feige even had press conferences about the possibility of a Cruise Iron Man. However it didn't work out, Cruise spoke about Iron Man saying:
“I don’t know. It just … they came to me at a certain point and … when I do something, I wanna do it right. If I commit to something, it has to be done in a way that I know it’s gonna be something special. And as it was lining up, it just didn’t feel to me like it was gonna work.”
5. Leonardo DiCaprio (Spider-Man)
While James Cameron was still to write and direct a Spider-Man movie, Leonardo DiCaprio was on the track of playing Peter Parker. The role eventually went to DiCaprio's best friend, Tobey Maguire
6. Liam Hemsworth (Thor)
It was originally the younger Hemsworth who auditioned for the role of Thor. However after running lines with his younger brother Chris decided to go for the role, and nailed it right away.
7. Sam Claflin (Harry Osborn)
In The Amazing Spider-Man 2, Claflin was rumored to be in the final three for the role of Green Goblin.
8. Kate Hudson (Mary-Jane)
For the the 2002, Spider-Man movie, prior to the casting of Kirsten Dunst, Sam Raimi approached Kate Hudson for the role. Hudson however turned it down.
9. Neil Patrick Harris (Nightcrawler)
He one of the finalists for the role Harris ended losing the role to Allan Cumming, due to the fact that Cumming had the ability to speak fluent German.
10. Emily Blunt (Black Widow & Peggy Carter)
Emily Blunt turned down both Black Widow in Iron Man and in Captain America the role of Peggy Carter, stating that "the part wasn't very good and the timing wasn't right."