He's the original superhero; the oldest there is, having been crusading for peace and justice across multiple mediums for over eighty years. In that time Superman has undergone many changes, upgrading his powers extensively, originally displaying the ability merely to leap over tall buildings, before gaining the full power of flight.
Along with the various changes to the core lore and myth of this iconic character, there has also been a plethora of alternate versions, inhabiting other universes, far-off futures, and even long dead pasts.
Across a spectrum of heroism, amorality, tyranny, and other stages in between this list details just ten examples of these alternate Clark Kents. With decades of Superman lore, and a myriad of universes from which to pull, Superman alternatives are in great surplus, so there are many more to explore beyond this list.
10. Superman Prime
This is a futuristic version of Superman from the 853rd century. His power has grown exponentially as a result of having become like the living embodiment of the sun; essentially a sun god.
He acquires these new powers after travelling the universe for many centuries, gaining more and more abilities along the way. After this exploration he moves his fortress of solitude from earth to the centre of the sun, where he resides for fifteen-thousand-years, the solar energy charging his powers to an unprecedented extent.
The reason for his retreat from earth is that his Kryptonian genetics allow him to live far beyond the years of those he loves. Lois Lane dies of old age along with the rest of his family, and so he passes his duties on to new heroes, and leaves earth.
Eventually he returns to heroism after his long hibernation in the sun, and resurrects Lois in a new form with a futuristic silver body to compliment his gold one.