Donald of House Trump, First of His Name, King of the Americans and Bad Hombres, Lord of the Fifty States, and Protector of the Realm.
Alternatively, if that's too obvious, we can take the Hapsburg approach and list every domain individually:
Donald I, Emperor of America, King of New York and California, Prince of Florida, Texas and Pennsylvania, Archduke of Illinois and Ohio, Grand Duke of Michigan, Virginia and Georgia, Duke of New Jersey, Washington, Arizona and Tennessee, Palatine of the Two Carolinas, Marquis of Indiana, Massachusetts, Missouri and Maryland, Count of Wisconsin, Colorado, Minnesota and Alabama, Prince-Bishop of Louisiana, Viscount of Kentucky and Oregon, Baron of Oklahoma and Connecticut, Basileus of Iowa, Lord Protector of Utah, High Chief of Arkansas, Heavily King of Nevada, Lord Provost of Mississippi, Caudillo of Kansas, Shogun of New Mexico, Jefe of Nebraska, Chief Mining Engineer of West Virginia, Supreme Pontiff of Idaho, First Sea Lord of Hawaii, El Yanqui Supremo of New Hampshire, Maine and Rhode Island, High Sheriff of Montana, Dictator of Delaware, Despot of Upper and Lower Dakota, Archfiend of Alaska, Great Khan of Vermont, Taoiseach of Wyoming, Governor-General of the District of Columbia, Lord Protector of Puerto Rico, and Supreme Overlord of the Associated Territories.
I think that's all of 'em.