Earth-1 is the re-imagine of DC Comics super-heroes set in the 21st Century.
Earth-1 was created by J. Michael Straczynski and Shane Davis.
Note: Earth-One was originally Sliver-Age DC Comics mainstream line, until after Flashpoint which was change to Earth-0 (Prime Earth) and graphic novels was giving the destination Earth-1.
Post-Flashpoint / Earth-1
Originally conceived as a new series of graphic novels existing in a new continuity, on a new Earth, separated from the current New 52 continuity, this would be reversed in the Multiversity guidebook, where the Earth-1 universe, still in formation, was revealed as the universe where all the events of the graphic novels happens:
"This freshly created universe is still cooling and yet unformed. Earth-1's known super beings -Superman, Batman, Wonder Woman and the Teen Titans- are at the beginning of their careers. Time and space are still pliable, and nothing here is certain".Multiversity Guidebook, page 29, January 2015.
Major Story Arcs
Post-Flashpoint / Earth-1:
Graphic Novels that take place in Earth-1