This page lists or shows all the heroes that have been in some sort of media and who could potentially be a part of Overwatch or included in the game at some point.
The following stills are taken from the animated short Recall in which Winston sends out a recall signal across the globe to all former Overwatch agents.
Appears on far left in "Group 1" and "Group 3"
Potentially on left in "Other 4"
Potentially the front man in "Other 3"
Potentially on lower left in "Other 1"
Appears on far right in "Group 1", center-right in "Group 2" and center in "Group 3"
The following are group shots that show some unknown heroes:
Other 4, the woman on the far right may also be the woman in "Other 3"