You can use the Steam Workshop as a good place to find mods. But I will give you some mods that I recommend.
Napoleon Total War Steam Workshop - Wix.com.Total War Centre has mods available for download, and visiting the Lordz website you can download their NTW3 p7.2 mod (very good mod for multiplayer!) NTW doesn't have a steam workshop unfortunately.Is Napoleon Total War in Steam Workshop? :: Total War.
