Some random SUF theories.

Earth-16 (War Never Ended) on this timeline, the Gem War never ended, instead the war went on for several more years till it gets to a point where humans got involved and fought back against Homeworld. the war lasted another 3000 years and the Crystal Gems won the earth with million casualties, Gems and Humans. in this timeline, humans has advanced technology thanks to the gems, but can't able to escape the medieval era, making this universe a fantasy future-like universe.

Earth-16 is discovered by me

Earth-18 (Alone) this is a bad timeline for Steven, on this timeline, the human government looked at the Crystal Gems as a threat, so they made an organization that would study the gems with the first order, shatter the Crystal Gems. they were successful but found a half-gem baby, to find out more about the gems they took him and used him for brutal tests years later. this Steven (or as he is known as Subject 815) is corrupted from all the pain he was given, now insane with a hatred of humanity, as he hopes that one day, he would destroy them.

Earth-18 is discovered by me

Earth-19 (Same History) this earth, as there was a Gem War 6,500 years ago, nothing on the earth and human history has changed, people celebrate holidays that was never celebrated in other timelines, there was another world war in the 30s to mid 40s and the world is similar to... ours.

Earth-19 is discovered by me

Earth-22 (Mad Steven) in this timeline, Steven and the Gems failed to get the ocean back from Lapis, and Lapis made an escape escape with the earth's ocean, making the planet a wasteland. on this earth, Steven blames himself for the fall of humanity and the earth, he spent the rest of his life driving through the wasteland to save what's left of humanity from corrupted humans. so it's basically a Steven Universe version of Mad Max.

Earth-22 is discovered by me

Earth-23 (Cyberpunk)

basically a Cyberpunk themed version of Steven Universe

Earth-23 is discovered by me (although a lot of people might made pictures of this)

Earth-26 (Superheroes) when Captain Universe throw his mighty shield all those who oppose his shield must yeid a universe where the gems are like superheroes, Steven in this Universe is Captain Universe! (which is basically Captain America)

Earth-26 is discovered by me

Earth-27 (Corruptverse) one of the horrible universe in the SU multiverse, it's a universe where death doesn't exist, so people rot instead of die, gems gets corrupted when shattered and basically there's no such thing as death. basically the Steven Universe version of Marvel's Cancerverse

Earth-27 is discovered by me

and that's it, want to see more, well think of world ideas and it could possibly be an earth, (note: if your Steven in your universe looks exactly like the canon Steven, then I'll not feature that universe)

SEE YA!