The Anti-Superman Gang debut in Action 376 (May 1969). They are kind of like the Superman Revenge Squad, in that they come up with really complicated ways of killing Superman, except they are all human criminals.
Throughout this story, by Binder, Swan and Abel, they try out a number of methods of killing Superman, with very little success. So little that Superman doesn’t even notice what is going on.
The attempt to kill him using his own costume moves the story almost into farce.
Finally, a serious effort is made, with a satellite spreading kryptonite. Superman dons his old faithful anti-kryptonite suit, but the gang has planned for that, with an element-changing ray that turns his suit to glass.
The story concludes in the next issue.
Supergirl’s long run in Action Comics comes to a close with this story by Leo Dorfman and Kurt Schaffenberger.
Supergirl gets blamed for an accident that robs one of Stanhope’s science students of her sight. When Supergirl is unable to cure her blindness, the student body as a whole turn on her. But then some aliens steal the entire science department.
It turns out the aliens stole the girl’s sight, and are now planning to steal everything in her mind. But their machine does not work, because Supergirl has taken the blind woman’s place. She defeats the aliens, and uses their tech to restore the woman’s sight.
Not a great story, but Supergirl gets promoted anyway, moving over to become the cover feature in Adventure Comics, while the Legion of Super-Heroes get demoted, taking over her spot in Action.