Jorok Goldblade
Member
Raven might actually be off limits because of Titans and TTG!. There's plenty of other villains that could work though. Nyssa would also make sense in a semi-mystical team. Slade could be haunted by Shado's actual ghost for a change.
Okay - new pitch.
Nekron is raising an army of all the greatest fallen warriors of the Arrowverse. Constantine puts together a team to stop him. Nyssa joins because of all the League of Assassins zombies, Slade joins because of Shado and Wintergreen.