There are a variety of sources for international data, and of course many intersect with other data topics like demographics, economics, etc. Two of the most popular are the World Bank and the United Nations.
UN Commodity Trade Statistics Database (UN Comtrade) contains trade data (imports, exports and re-exports) from countries world-wide. For each country annual data can be retrieved by commodity and trading partner. Commodity is defined by either standard international product codes or international industry codes.
UN comtrade / United Nations Statistics Division .
Includes all data published in the printed Yearbook of international organizations (Volumes 1A, 1B, 2, 3, and 4), Who's who in international organizations, and the whole Encyclopedia. Includes the searchable databases: Global strategies - solutions, Human values, Human development, Patterns and metaphors, Bibliography (issues), Integrative concepts, Network visualizations, and Transnational associations.