Buffalo 5 Girls and Memoirs of Amorous Gentlemen are two in-progress works by Anno Moyoco, each about ten chapters right now. Both tackle prostitution, sexual violence and slavery, and the challenges of loving men in a patriarchal world.
I’m generally not a fan of christening things “feminist” or “not feminist” — it’s rarely so simple, the world can’t be neatly arranged into good and bad categories, and arguing about whether or not an author/work belongs in the Club virtually always comes at the expense of actual thematic discussion and analysis.
That said, if you’re looking for manga with strong feminist themes, I haven’t encountered anything quite like Anno’s work. Add her gorgeous art on top of it and she’s easily my favorite mangaka right now.
(Both of these works are on Crunchyroll, and if anyone would like my login info to read them/watch shit just let me know.)