edit: i am going to start going through the comments and updating this list accordingly. didn't expect so many lol, but happy to aggregate leftist music projects.
BLACKWATER SNIPER - a fusion of speedcore, noise, and extreme metal/punk. lyrical content is anti-war and anti-imperialist.
Blue Scholars - smooth and silky revolutionary jazz rap
CHOP CHOP CHOP CHOP CHOP CHOP CHOP - more noisy electronic metal. i've only listened to his debut, Extreme Creep. has a track on it protesting ICE, released nearly 6 years before the 2nd trump admin.
Christ vs. Warhol - a goth / deathrock band. Dissent touches on anti-capitalism quite a bit.
Emma Goldman - i feel like the name sums it up. queer anarchist screamo.
fromjoy - unique, VERY angsty vaporwave-infused metalcore. including them on this list is a bit of a stretch, but i really enjoy and recommend them. their song "machine" on their self-titled LP is anti-cop.
Godspeed You! Black Emperor - probably one of the most well known on this list. GY!BE is an anarchist music collective that makes instrumental post-rock. their latest untitled album is a protest album against the genocide in palestine.
Machine Girl - another comparatively more known project. digital hardcore. my favorite release of theirs is the metal-tinged U-Void Synthesizer. the song "Fortress Destroyer" off that album is about killing nazis.
Midori (Spain) - jungle / digital hardcore with occasional samples about anarchism
Orchid - anti-capitalist screamo/emoviolence
Panopticon - atmospheric black metal. one of the more well known faces in the RABM (red & anarchist black metal) movement. stopped sharing lyrics after the Kentucky LP. a lot of his lyrics on that album are about the miner strikes and early labor movement in kentucky.
Pig Destroyer - grindcore band. ceased writing political lyrics very early in the band's lifetime. Head Cage has an anti-cop song though.
Primitive Man - sludge metal band. genuinely a contender for the heaviest band of all time:tm:. a good portion of their lyrics on Caustic are anti-capitalist.
Pyrrhon - avant-garde, technical, dissonant metal band. Exhaust has a few political lyrics.
Sankara - communist vegan war metal. named after thomas sankara.
Thou - diy anarchist sludge metal. GREAT music, but sometimes a little sketchy. kinda gives egoist vibes
Vermin Womb - grindcore project related to primitive man
The only one I know of is a Filipino-American rapper named Bambu, who's got some songs named Intifada and Chairman Mao.
I also really like the Peruvian Cocaine song by Immortal Technique and some others, but all of the other songs I've heard by Immortal Technique, while some are very heartfelt or deal with serious issues, aren't particularly political.
I'd love to hear of some others, too!