The dog Romero is named after director George A. Romero, who pioneered the use of zombies (the living dead) in horror films.
Every episode title ends with "SAGA".
The name of the show is actually officially known as Zombie Land Saga, and not Zombieland Saga, to try not to be confused with the comedy horror zombie movie series Zombieland. Beyond the similar names and zombies, it has nothing to do with the Zombieland movie series.
Tai Yamada's voice actress is the only voice actress absent from the live action version of the idol group Franshushu when they preform in public. Which is considered odd since she was a part of Peach Hips (an idol band composed of all the voice actresses who played the inner Senshi in Sailor Moon) and this have experience as a member of an idol group.