The Declaration of Independence, Washington crossing the Delaware, the Constitutional Convention: all great moments in America's history. But you know what would have made them better? Alchemical guns and airships. Let's look at some alternate stories of the American Revolution.
It's hard to imagine a group of guys whose historical lives already sound more made up than the Founding Fathers. Aaron Burr shot a dude and then got tried for treason, Thomas Jefferson and John Adams both died on the same day: the 4th of July (show-offs). And George Washington...where do you even start with him? But my personal favorite founding father, and seemingly a favorite of alternate history, is Benjamin Franklin. You have to work hard to make a more interesting fictional life for a man who gained international renown for playing with lightning and inventing an instrument that was reported to drive men mad. But alternate history fiction, bless it, has found ways.
The Age of Unreason series by J. Gregory Keyes is a set of alternate history books predicated on the idea that Newton's fascination with alchemy in his later life has borne strange fruit. As a result Europe has access to ships that repel against the earth, blunderbusses that can shoot the elements, and alchemical fax machines. Although the story follows many characters the alternate life of Benjamin Franklin is a central narrative. In The Age of Unreason timeline Franklin spends time in England studying under Sir Isaac Newton, invents alchemical equivalents to many of his own inventions (as well as a few more, like the phone and the television) and returns to America eventually declaring independence for the colonies and a new capitol of Charleston, South Carolina. Believe me, the choice of capitol makes a lot more sense when you read the books.
Franklin also plays a large role mentoring the protagonist of The Year of the Hangman, a young adult book by Gary Blackman where Benjamin Franklin (and Benedict Arnold) are among the last hold-outs in a universe where the revolution has failed and George Washington was hung for treason. Blackman's novel brings us to those universes in which the colonists lost the Revolution.
Perhaps the most interesting part of that scenario is all the different ways it could have happened. In For Want of a Nail, an alternate history novel by Robert Sobel that acts as a high-school textbook for an alternate reality where the US lost the Revolutionary War, the divergence is traced back to Benedict Arnold losing the Battle of Saratoga. Here's a map of Sobel's alternate America:
In The Two Georges by Richard Dreyfuss (yes, that Richard Dreyfuss) and Harry Turtledove, Washington reaches a compromise with Britain resulting in America remaining under British rule even into the 1970's.
Of course, even if we manage to win the war America still exists in a state of flux for quite some time. Most notably there's a great deal of Alternate History fiction surrounding the writing of the constitution. In Disunited States of America by Harry Turtledove and The Forest of Time by Michael Flynn, the colonists can never agree to a binding constitution and instead become separate, warring states. And in King Julian by Tom Gatch, George Washington consents to becoming the King of the Americas where his descendants still rule today.
This isn't even covering the way-out-there alternate Revolutionary War fiction, such as the unintended consequences from S.M. Stirling's Domination series in which the British gain Cape Town from the Netherlands during the Revolutionary War and end up creating a racist, classist South African super-state.
Fun Fact: Alternate stories of the creation of independent American States are one of the oldest historical what-if scenarios. King Julian for instance is from 1954. Aristopia by Castello Holford imagined the discovery of a large gold horde in Virginia leading to a state modeled on Thomas More's Utopia and that was written in 1895.