http://www.comicbookresources.com/article/who-are-legends-of-tomorrows-justice-society-of-america

The season finale of "DC's Legends of Tomorrow" rattled the time-travel drama's status, altering the team's roster, introducing Rex Tyler (aka Hourman) and revealing that the Justice League's precursor, the Justice Society America, exists in The CW's Arrowverse. It's, of course, a major revelation that sets the stage for Season 2, and raises plenty of questions -- not the least of which is, "Who are the members of the TV Justice Society?" We've turned to the DC comics and come up with a list of team members who could potentially appear on "Legends of Tomorrow." Power Girl Although a Supergirl appearance is likely -- especially now that her series has moved to The CW from CBS -- "Legends of Tomorrow"

from their list:

Power Girl - I like it, cast Carrie Keagan immediately

Doctor Mid-Nite - meh, maybe for a short arc, but not as a regular

Sandman - another character that would probably work better in a short stint

Spectre - as mentioned, he appeared on the in-universe show Constantine, so it could happen

Red Tornado - no not that one, but the other one; we already know she is scheduled to appear in season 2

Starman - in some form or other will probably appear, it just seems a likely scenario

Doctor Fate - a favorite of mine from the old comics, he'd be a great addition to the team

Liberty Belle - probably more suited to a guest appearance

assuming that most of the other JSA members are not available to the show - no Batman, Superman, Wonder Woman, Black Canary, Green Lantern (unless the can use the original Earth2 version) Wildcat, then that leaves Johnny Thunder, Mr Terrific and Sergeant Rock.