Batman Superman #1 1st cameo appThe Shazam Who Laughs

Batman Superman #2 1st app of Superman Who Laughs, 1st full app of Shazam Who Laughs

Batman Superman #3 1st appearance of the Dark Multiverse Blue Beetle

Batman Superman #4 1st full appearance of the Secret Six, heroes infected by the Batman Who Laughs toxin: Jim Gordon, Donna Troy, Hawkman, Shazam, the Blue Beetle, and Supergirl, cameo

Batman Superman #5 1st full team appearance of the Secret Six

Batman Superman #16 1st appearance of Spider Lady, Dr. Atom, the Unknown Wizard