"These textbooks are either in use at academic institutions or have been produced by subject matter experts affiliated with academic or professional institutions." Contains 686 textbooks. (as of April 2 2020)
For the duration of this crisis, all Ohio State University Press monographs, and the linguistics textbook language files, will be open and free to use through the Ohio State University Libraries’ Institutional Repository, The Knowledge Bank.
University of Michigan press is removing barriers to read all their ebooks (you must still purchase the book to download it, but you can read the entire book in your browser for free). For more info read the relevant blog post here: https://blog.press.umich.edu/2020/03/ump-covid-19-free-access/