Assuming you are talking about souvenirs and gifts for friends and family, here are some ideas:
-Food items: Think local specialties that can't be easily found back home. For example, if you're from Europe, you could bring back some good old American peanut butter, or if you're from Asia, you could bring back some delicious maple syrup.
-Clothes: Again, look for items that are unique to the USA. For example, you could bring back a I  NY t-shirt, or a cowboy hat.
-Souvenirs: There are plenty of touristy things you can bring back, from keychains to snow globes. Just make sure to avoid anything too tacky!
-Gift cards: If you're not sure what to get, a gift card to a popular American store (like Macy's or Target) is always a good idea.