THINGS RELATIVELY RELATED THAT CAME AFTER
The heroes participate in the cleanup efforts in Metropolis. The event's aftermath leads to Joe Martin becoming the Atomic Skull.
Captain Atom and Monarch become involved in an alien plot that begins when Armageddon 2001 #2 left off. The pair, through a combination of Captain Atom's unreliable powers and Monarch's semi-functional armor, make temporal jumps while fighting each other in various time periods, including pre-historic dinosaur-filled times, ancient Rome, and the Wild West before finally returning to something close to when they left.
Superman and Waverider encounter the Linear Men. Waverider laments no longer having a connection to his own timeline which has been eliminated by the events of Armageddon 2001. The present-day Matthew Ryder is revealed to eventually grow into adulthood and become a member of the Linear Men instead of becoming Waverider, in essence revealing there are two Matthew Ryders with interests in preserving the timeline.
Only partially connected due to the involvement of Waverider. This mini-series tells the story of how interdimensional demon Abraxis seeks to enter the main DCU reality through the use of his daemen. Waverider assembles heroes from across time to battle them, similar to how the Monitor assembled heroes during Crisis on Infinite Earths. The main thing to take note of is that the Justice Society of America is returned to the main DCU after having not been seen since the events of Last Days of the Justice Society of America.
Parallax and Extant (formerly Monarch) attempt to rewrite time and reality. Waverider and Earth's heroes join forces to stop them. At the end of the story, the DCU timeline is partially rewritten in an effort to smooth out continuity errors.
MY THOUGHTS: Pretty much Waverider shows up here and there, but he really has no major connection to the major DCU at large. He pretty much becomes a part of Superman's cast and appears alongside the Linear Men. Monarch becomes Captain Atom's nemesis somewhat. After Zero Hour (which is a confusing mess where Monarch/Extant and Waverider are concerned) a different Monarch appears in the DCU which is Nathaniel Adam (as originally intended) but Captain Atom also exists. In short, things never really get sorted out smoothly, I'm afraid.
PERSONAL NOTE: My thanks for all of you taking this journey through an old crossover with me. I've had fun going through these and I hope everybody has had fun reading along.