These resources have some textbooks, but have a LOT of other types of resources: worksheets, exercises, simulations, case studies, lectures, syllibi, videos, and MORE.
MERLOT is a curated collection of free and open online teaching, learning, and faculty development services contributed and used by an international education community. It is a product of the California State University System partnering with education institutions, professional societies, and industry.
Created by Abbey Elder at Iowa State University, this book provide instructors with an introduction to the use and creation of open educational resources (OER). The text is broken into five sections: Getting Started, Copyright, Finding OER, Teaching with OER, and Creating OER. Although some chapters contain more advanced content, the starter kit is primarily intended for users who are entirely new to Open Education.
Pressbooks is a professional authoring and self-publishing platform to create an open textbook, to edit and adapt an open textbook, or to create and edit any other type of online resource.
OpenStax College offers free, peer-reviewed textbooks in a select number of disciplines. These texts have been designed to meet course standards in scope and sequence.
All OpenStax textbook content is under a Creative Commons attribution license, allowing for the editing and customization of content to suit specific course needs.
Multiple institutional sponsors, hosted by University of Minnesota - Twin Cities. "This library is a tool to help instructors find affordable, quality textbook solutions. All textbooks in this library are complete and openly licensed." UMKC is a member of the Open Textbook Network (OTN), which supports the Open Textbook Library, through MOBIUS.
Organized by engineering discipline. Note that some specific disciplines have been grouped within a larger discipline (e.g., transportation engineering texts can be found in civil & environmental engineering).