These are sources for data on multiple countries and multiple industries.
Most industries and countries have specialized sources that you may
want to seek out after you have focused on a particular policy.
APEC Tariff Information
CIA, World Fact Book
Economist Intelligence Unit*
FAOSTAT, Food and Agriculture Organization of the UN
Global Trade Alert
IMF Data*, International Financial Statistics, Direction of Trade (DOT), and Balance of Payments (BOP).
ITA Trade Data and Analysis
World Economic Outlook April 2020, IMF
NBER Data
OECD Data
Temporary Trade Barriers Database, World Bank
Trade and tariff data, World Trade Organization
Trade Competitiveness Map, International Trade Centre
Trade Policy Review, selected countries, World Trade Organization
United Nations Data
World Bank Open Data
World Development Indicators 2009, World Bank

*Available only through U of M subscription, with your UM uniqname and password.