David Rovics is an anarchist musician that has been releasing some of the most topical and incisive leftist music since the nineties. It's just really good music too. I've put together a list of my favorite songs of his:
Saint Patrick's Battalion
It's about Irish immigrants who went to fight in the US-Mexico war and ended up deserting the american army and fighting side by side with the mexican army. They're know in mexico to this day as "Los Patricios".
They All Sang The Internationale
About the day Katharina Jacob was rescued by Russian troops, on May 1st, 1945. Katharina was a German communist organizer who was arrested by the SS and was then saved by the red army.
Commandante Fidel Alejandro Castro Ruz
After Fidel Castro died, David wrote a song about Castro's leadership of Cuba and all the development brought by the Cuban revolution.
My favorite one, it's a call to arms for all the working class. A call for unity and solidarity among all workers. It just represents all the wholesomeness in recognizing each other's struggles and setting a common goal.
I'm a Better Anarchist Than You
A satirical song about how some people in the movement get caught up in one-upping each other for being the most leftist and having the purest ideology possible.
There are many more songs and all of them are worth checking out, it's good to know that leftist folk-ish music didn't stop existing after the 60's.