3-D Man

A-Bomb (HAS)

A.I.M.

Aaron Stack

Abomination (Emil Blonsky)

Abomination (Ultimate)

Absorbing Man

Abyss

Abyss (Age of Apocalypse)

Adam Destine

Adam Warlock

Aegis (Trey Rollins)

Aero (Aero)

Agatha Harkness

Agent Brand

Agent X (Nijo)

Agent Zero

Agents of Atlas

Aginar

Air-Walker (Gabriel Lan)

Ajak

Ajaxis

Akemi

Alain

Albert Cleary

Albion

Alex Power

Alex Wilder

Alexa Mendez

Alexander Pierce

Alice

Alicia Masters

Alpha Flight

Alpha Flight (Ultimate)

Alvin Maker

Amadeus Cho

Amanda Sefton

Amazoness

American Eagle (Jason Strongbow)

Amiko

Amora

Amphibian (Earth-712)

Amun

Ancient One

Ancient One (Ultimate)

Angel (Angel Salvadore)

Angel (Thomas Halloway)

Angel (Ultimate)

Angel (Warren Worthington III)

Angela (Aldrif Odinsdottir)