Some of the film's Suicide Squad members, such as Quinn and Deadshot, are series regulars. However, others, such as Killer Croc, have never been on the team prior to the 2016 reboot, which was presumably inspired by the film.
Which of the following characters were ever members of Task Force X in any of the mainstream comic DC universes, prior to the Rebirth relaunch?
According to the Wikipedia page for members of the suicide squad, the only one listed that was never a member of the team prior to rebirth is Killer Croc. Out of all the other incarnations, Pre and Post rebirth, Joker has never been part of the squad.
All others have been in the various incarnations of the team (some members being different people under the same identity. Looking at you, Captain Boomerang).
The member that has been in almost every version of the team going back to the Silver Age is Rick Flag (Jr). The next members who were in the most incarnations would be Captain Boomerang and Deadshot.
Katana was offered a position to help on a mission, but declined.
