Bruce Banner/Hulk
Clint Barton/Hawkeye
Natasha Romanoff/Black Widow
Steve Rogers/Captain America
Thor Odinson
Tony Stark/Iron Man
Agent Phil Coulson
Loki Laufeyson
Pepper Potts
Nick Fury
Maria Hill
From this picture:
The cast of the Avengers signed this card as if they were the characters :)