Xiaomi's A-series phones (A1, A2, "A2 lite" - a misnomer, in some ways it's better than the A2) are quite nice especially for the price, can be unlocked very easily (for installation of a custom ROM) and are sold globally including in the U.S. Their MIUI-using phones (and Huawei's, with their EMUI) are a different matter, though.