Source: Adventures of Superman vol.2 #46-48 (2014) Type: Non-canon
What if you took every Superman story ever and put it in a blender? You might get "Strange Visitor" by Joe Keatinge, a story initially told by an elderly Kamandi as Earth's population heads for the stars before the planet blows up. It starts in the 1930s or 40s, with the World's Finest duo in their very first costumes teaming up with Dracula to fight Frankensteins, and features such incongruities as Professor Potter apparently raising the Toddler of Steel!
By the second chapter, it's 2013, Lois Lane is an old lady and Superman is friends with Mxyzptlk, but he hasn't aged. Everything that ever happened to Superman in the comics happened over the decades, including all that crazy Red K stuff from the Silver Age AND the 70s movie stuff too!
In the last chapter, Kamanda is long since dead and is no longer narrating, because, hey, it's the end of the universe. Superman has split himself into thousands of selves, each representing an incarnation you might have already glimpsed in Reign of the Supermen. Superman MMCIX is the Unknown Superman of 4500 A.D., for example, while Superman MCMLXIII is the one with an ant head. And then there's Superman Null.
He's at the center of things, holding the cosmos together. He absorbs the Super-Sentries back into himself (at least, the ones that survived this long), and when he lets go of the cosmic core, our universe dies and another is born. And Superman will be there as well, forging ahead and keeping the peace...