The flowers we always see with Carol (Melissa McBride) on her wardrobe or even in her new home are a direct reference to the "look at the flowers" moment in season 4.
Jadis (Pollyanna McIntosh) is the name of the witch in C.S. Lewis' The Lion, The Witch and the Wardrobe.
Daryl (Norman Reedus) and Richard (Karl Makinen) are standing in front of the Smokey and the Bandit (1977) trailer when they are preparing an attack on the Saviors.