Spell the Avenger #23

Below are the pictures of several Marvel characters who have all been a member of the Avengers, or some branch or alternate version of the Avengers. Name each character. Once you have named each pictured character, the first letters of each character's name will spell the name of a mystery character (who has at some point been a member of the Avengers). Supply the names of all the pictured characters as well as the mystery character in order to complete the quiz.