Consider donation through posting online, non-profits, schools, community organizations, or companies that specialize in office furniture (i.e. cubicles) redistribution. Most small thrifts do not accept large volumes of or office furniture in general, unless it's very good condition that can be used in a home.
Consider reuse, repair, reupholstering, and remanufacturing. Find out how they are good for people, the planet, and the business from Center for Environmental Health. If you need to purchase new furniture, use their guide to Choosing Healthier Furniture.