Famously tariffs on steel. The European Union was originally created as a tariffs union, and the official name was "European Coal and Steel Community", which then slowly grew into the EU we have now.

Steel tariffs are still a core part of the EU, and are aggressively used today.

The European Commission has all the information on tariffs you might be interested in at this page:

https://taxation-customs.ec.europa.eu/customs/customs-tariff...

The European Council has a more general information page:

https://www.consilium.europa.eu/en/policies/eu-tariffs-expla...