It depends what you have already obtained FW ???
On the DLS, under buildings/structures, type in the word school, bank, etc, you can see which are American based rather than European, some of the Australian ones may be useful to you as they are generally wooden structures that may fit quite well into an American setting. There are lots of farm buildings, schools, etc, etc.
Kilanziom did a Chrysler Building for New York and some other excellent skyscrapers, hotels, banks, and neighbourhoods for American and Canadian cities, search under his kuid 173943. Of course, our veteran creators Dave Drake and Ish6 have both done hundreds of American city and town buildings and Leeferr has done a school and some other wooden buildings for US villages, etc.
You could also have a look on the Trainz Pro Routes website, as in the route download section are a few buildings for each layout that may be worth downloading also, and in the general download depot, search for euphod's name as he did some gas station signs and other useful stuff, it's worth having a good look on the TPR site.....
Happy hunting.....
Cheerz. ex-railwayman.