Batman v Superman: Dawn of Justice contained a fair amount of Easter eggs in addition to all of its world building elements.
Justice League will at least be heavy on one of those as the producers have said the film will include its share of cameos and Easter Eggs for eagle-eyed fans to catch.
During a recent set visit, ComicBook.com's Brandon Davis was on hand when Producers Deborah Snyder and Charles Roven were asked if we would "see more associates from The Flash, Iris West or something like that?"
They were hesitant to confirm any details, but they did confirm Justice League will have some cameos and fun drop-ins for fans.
Snyder: There might be some cameos of people. You know. We kind of like to do that so we'll see.
Roven: We do like them and to put Easter eggs in these movies and so..."
Teases from Batman v Superman will also be expounded upon, such as the Mother Box. It was briefly referenced in BvS, but will play a much bigger role in Justice League. The same goes for the Parademons, who were seen in the dream sequence in BvS, and while they might not look exactly the same in Justice League, they will still play a part in the film.