"Justice League Unlimited" is a sort of reinvention of the "Justice League" series which was, itself, a continuation of the Batman and Superman shows. While the entire run of both "Justice League" shows is available on TVD, the sets and episode order is a little confusing if you're going by what you rember from the different seasons. So I will handle them by volume rather than by season. The sets don't offer a great deal but do have a few exciting extras.