Boycott US

For sure! Switzerland is definitely the biggest example, though there's also Liechtenstein and arguably Cuba (not saying it is outright). If I were to play devil's advocate I'd say that those are all semi direct democracies, though considering how abstracted they all are from representative democracies in general I'd also say that it hardly makes a difference from a relative standpoint.

In Switzerland's case, there's no need to register directly as a voter, and every citizen has an opportunity to vote on various issues on about a quarterly basis, or 4 times per year. People can also vote on appending the constitution and can vote against bills approved by authorities. According to the Politics of Switzerland Wikipedia page:

The people also assume a role similar to the constitutional court, which does not exist, and thus sovereignty resides with the people, who exercise supreme political power and act as the guardians of the rule of law. According to the V-Dem Democracy indices, Switzerland was, in 2024, the most participatory democratic country in the world and Freedom House has Switzerland as one of the freest countries in the world, scoring 39 out of 40 points on political rights, and 57 out of 60 on civil liberties for a total of 96 out of 100 in 2024.