jonny quest from the '90s I freakin LOVED that show !!
who says the Punisher would be weak? if they all-of-a-sudden came out with JL:Unrated, he would be awesome
Swat Kats would be cool if they joined, they could drop bombs on Luthor snd stuff
Pirates of Dark Water would be GREAT, but they would be hard to include in the plot of Justice League, another awesome series that didn't get much recognition (canceled in mid-season, so stupid)