can you list some great mods.
Sounds like you'd be up for the Wolfshanze Mod (link in sig-line below).
It's a Civ-flavor-mod, combined with some new units in the biggest gap Firaxis left in the game... the Industrial Age... and a few new civs (Austria, Poland & Vietnam).
First, the "flavor mod" aspect makes each and every civ look and feel completely unique... Aztec cities look Aztec... Chinese cities look Chinese... Russian cities look... well... Russian. Same for the units... Germans look German, Japanese look Japanese, etc, etc... the uniforms and equipment are specific to each nation (Germans will fly Messerschmidt fighters, Americans will fly P-38 Lightnings, etc, etc). This "flavor" aspect is covered from the dawn of civilization in 4000 BC right up to the very end of the game in modern times.
As for the Industrial Age enhancements, the Wolfshanze Mod adds units missing from that age... especially coal-fired navies, ocean-going ironclads, pre-dreadnoughts and dreadnoughts, WWI units such as early tanks and biplanes.
Gameplay-wise, the game plays the same as it always has... you can still play from 4,000 BC to modern times just like always... tech progression is the same, old strategies still work the same, you just get better looking units, better looking cities, more units to play with in the industrial age, and better naval options.
Here's a video teaser of what you get... if you see it in the movie clip below, you get the equivalent of it in the Wolfshanze Mod... link for the mod is in my sig-line.