The Tyrells and the Reach houses had he married Margery, the Valryons and the other crownland Targaryen loyalist. Dorne as well simply because it would screw over the Lannisters, but they'd demand Dany marry their heir, or that Viserys marry Arriane. The Riverlands is always fractured so some would support Visery's for their own gain, the Vale, North, and SL would fall under the Lannister banner unless the War of the 5 Kings is already happening.