Egalitarian and materialist ethics, shared burdens civic for shared burdens living standard for everyone. Usually when I play Stellaris I aim to free all slaves galaxy wide.

shared burdens is basically the socialism civic, but if u are egalitarian u can always use the utopian abundance living standard which which is pretty communists, and if u have pacifist u can impose ideology on other empires letting u spread the socialism thru out the galaxy.

Also there is an advisor called the worker which is based as fuck.