The Washington 45 are "courses selected from within the general education categories... at a public community, technical, four-year college or university in Washington state that will be able to transfer and apply a maximum of 45 quarter credits toward general education requirement(s) at any other public and most private higher education institutions in the state." More information on the Washington 45.
Below is a list of open textbooks and course materials in this Google spreadsheet embedded below. These are available for each of the courses listed below. Download your own copy.
Source: "Washington 45" by Open Washington: Open Educational Resources Network is licensed under CC BY 4.0