I see that there are many kinds of organizations, but I was surprised to find that cooperatives are not among them. I do find specific kinds of co-ops listed under nonprofits, but this overlooks the fact that a great many kinds of co-ops are not, in fact, nonprofits. They are businesses, but they are distinct enough to merit a category of their own. so, I'm proposing...

schema.org › Thing › Organization › Cooperative

The only property I would propose for it is "bylaws," with the Expected Type of CreativeWork or URL.