United States: I'm technically still a registered Democrat but I will very likely register to vote when I move to Illinois as a Green or an Independent.
United Kingdom: Trade Unionist and Socialist Coalition
Scotland: Scottish Socialist Party
Wales: Plaid Cymru
Northern Ireland: Sinn Fein
Canada: New Democratic Party
Quebec: Quebec solidaire
Australia: Australian Greens
New Zealand: Green Party of Aotearoa New Zealand
France: Left Front
Spain: United Left
Germany: The Left
Italy: Left Ecology Freedom
Austria: The Greens - The Green Alternative
Denmark: Red-Green Alliance
Norway: Socialist Left Party
Sweden: Left Party
Finland: Left Alliance
Iceland: Left-Green Movement
Japan: Japan Communist Party
Taiwan: Democratic Progressive Party
South Korea: Justice Party
Illinois doesn't have party registration.
Excellent. Then I'll just join Socialist Alternative and be done with it.