Below is a list of species, locations, etc., which originally appear in the DC Comics and other media prior to the episode's airing, by appearance.
Allusions to the comics
- Main article: Characters from the DC comics
- In the comics, the company is known as Queen Industries or Queen Enterprises. It has been teased that in the future, it will be renamed as Queen Inc.
- In the comics, the company is also known as Kord, Inc. and Kord Enterprises.
Concepts first appearing in The Flash:
Concepts first appearing in Constantine:
- Great Darkness ("")
Miscellaneous nods to characters, objects, concepts or groups first appearing in Arrow:
Miscellaneous nods to characters, objects, concepts or groups first appearing in The Flash:
- Girder ("")
DC's Legends of Tomorrow
Miscellaneous nods to characters, objects, concepts or groups first appearing in Legends of Tomorrow:
- Waverider ("")
Allusions to other media
Companies, corporations and businesses first appearing in Supergirl:
- Luthor Corp ("")
Locations first appearing in Batwoman:
- Cartwright house ("")
Items first appearing in Supergirl:
- Omegahedron ("")