The Colorado State University (https://wac.colostate.edu) generously shares the WAC Clearinghouse resources published or made available in partnership with NCTE, Utah State University Press, and others (now more than 115 volumes) as well as the journal articles, which are available for free download in open-access formats. In addition, the Colorado State University offers a range of resources that might be of use to instructors and students, including Resources for Instructors (including more than 25 Teaching Guides and 16 Faculty Tip Sheets) and Resources for Writers (including more than 80 Writing Guides and a list of Open-Access Textbooks).
You can visit the Colorado State University Resource pages at https://wac.colostate.edu/resources. And you can search the site from any of its pages.