Not overtly leftist, but I've been reading Mitsuboshi Colors lately. It's just a cute little slice of life gag comedy, about a trio of little girls. But it weirdly has some radical politics thrown in?

The little girls have declared a random beat cop who works in the park they hang out in as their mortal enemy. At one point, the girls call him "A lapdog of The State" and there's this whole anti-landlord bit

So occasionally the girls will be used by the author to state some anti-capitalist political position, so that's fun.