Bring the Jubilee is a pretty massive confederacy wank, with the Confederacy not only completing pantsing the US but going on to conquer all of independent Latin America.
The (sadly deceased) John J Reilly's "Irish Empire" setting is one hell of an Irish-wank, mapped by SRegan here.
The Man in the High Castle is of course the classic Axis-wank.
GURPS Alternate Earth's Shikoku-Mon is an absurd Japan-wank, with a Japanese ethnic population (mostly in the home islands, Manchuria, NW America and New Zealand) bloated to 750 million ruling two-thirds of the world's population.
Thomas Harlan's SF/AH blend House of Reeds and sequels  has a Japanese-influenced Aztec empire as the world's dominant power and an interstellar explorer
 Which I need to read one of these days, if only for Map