Trade and economics drive much of the politics in Valterra, but indirectly in the main part. Before the Lykenem Empire fell, it was very segregated, with various portions of the Empire devoted to differing production, and a robust system of roads and an obscure, lost mass teleporting system (mysteriously called the Unim) moving the goods. This segregation of goods producing areas means that even over five hundred years later, the city-states are interdependent on one another for goods they don’t (or can’t) produce locally.
Much of the inter-national commerce is carried by the merchant clans because they are neutral and dependable; but by no means do they have a monopoly- especially in local trade, where they usually do not dabble. Local trade can be inside a city-state, or even with neutral and friendly neighbors. Beyond that, though…
Each city-state has a few goods that they export and import regularly, which are detailed on their page.