If there is a political self-description category in future surveys, another option possibly worth adding is "anarchist". Yeah, it's rare, but the closest option available was "socialist", which is still very dissimilar.

Incidentally, for those who are interested in political categorizations that might translate better across countries (and who have an OkCupid account), check out the Political Objectives test. A caveat is that, as the test itself notes, it is still specific to the countries and centuries that constitute the modern world, as "The assumption behind this test is that the three most important objectives of all-issues political movements in the modern era have been Equality and Liberty and Stability."