There are 6 USA trading cards tracked on HobbyCardIndex, spanning Soccer, Hockey. The most valuable is the USA #FWC8 at $2.94 raw.

Source: HobbyCardIndex · Updated daily · https://hobbycardindex.com/players/usa

USA Cards

6 cards · Soccer Hockey

All USA Cards

USA #FWC8

USA #B5

USA [Lower Right] #205

USA [Upper Left] #202

USA [Upper Right] #203

USA #545