I have an insert-noun-punk setting.
It started in the late 18th / early 19th century with clock-punk, mostly in the form of spies using clockwork gadgets in The Great Game, especially once Napoleon came on the scene. However, it also notably featured big suits of clockwork armour: They required a special winding tower and a team of draught horses to wind them, and could only operate for around five to ten minutes before winding down, however that was more than enough time to punch a hole in the enemy lines for conventional troops or cavalry to exploit, and the clockwork suits were basically impervious to anything sort of a direct hit from field artillery (which they were generally fast enough to avoid while wound up). Invented in the H.R.E., but adopted by France, Britain, Prussia and Austria they were situational weapons, but very powerful when used correctly.
A few French families which emigrated to America took their family armour with them. Their descendants ended up as officers in the confederate army, and some bright spark had the idea to replace the main-spring with a steam boiler and coal box extending the operating time from minutes to hours. It was so successful that soon purpose-built suits of steam armour were a main-stay of the Confederate army, and before long were adopted by the union army, too. In addition to iron-clad steam-ships, submersibles and various other innovations signaled the shift from clock-punk to steam-punk.
By the mid 19th century the world was basically your typical steam-punk setting, complete with analytical engines, massive factories fueling vast empires, and even giant airships thanks to the invention of the anti-gravity substance known as 'Cavorite'.
When the Martians attacked Earth in 1880 these technological advancements allowed humanity to make a proper fight of it, and just as the war was settling down into a WWI-style meat-grinder the molluscs started dropping like flies due to Earth diseases. Cond...