This is the World War II extra units pack originally hosted on the Firaxis website. These were included in the Play the World expansion, but did not carry over into Conquests. Icons are already present in the Conquests units32.pcx; a collection of official and third-party PediaIcons can be downloaded here. To install, copy the 'World War II' folder to Civ3PTW/extras.
Included in this pack:
See this pack for infantry.
PTW WWII Unit Pack 2 2016-10-05
PTW WWII Unit Pack 2