Ahh, the Confederate States of America! Who wouldn't love to see the Stars and Bars flying from Richmond to San Diego and from St. Louis to Panama City? A society that combines the Antebellum Era with the Industrial Revolution. A world where men in butternut smash all before them, and where the color of your skin dictates the content of your future. Where a gold dollar is refered to as a “Stonewall.” Where the national anthem is “Dixie,” and don't you forget it! Where the most famous Founding Fathers include Jefferson Davis, Robert E. Lee, Judah Benjamin, Alexander Stephens, Christopher Memminger, and (spiritually) John C. Calhoun.
Like the Third Reich and the British Empire, the CSA also figures prominently in alternate history, and is considered to be one of the most overused scenarios anywhere in the genre. Also, discussions about CSA scenarios tend to get political very quickly, or to focus on the question which side was “right” in the American Civil War, and what started the American Civil War.
Bring the Jubilee by Ward Moore (novel): the South wins the Battle of Gettysburg, and goes on to conquer and annex most of the Western Hemisphere, achieving superpower status in the process; the story is considered an early classic in the genre of alternate history.
Guns of the South by Harry Turtledove (novel): A group of early 21st century members of the Afrikaaner Weerstansbewging go back in time to 1864 and give Robert E. Lee's desperate Confederates a shipment of AK-47s.
TL-191 by Harry Turtledove (novel series): Robert E. Lee never loses Order 191 in 1862, leading to an independent Confederacy and a very different world; the series has ended with the Confederate States utterly destroyed and re-absorbed back into the USA after a World War II-like conflict.
The Wild Blue and the Grey by William Sanders (novel): A standard Confederate victory scenario, but the focus is on the CSA sending troops to Europe to help Britain and France in World War 1.