List of open textbooks from OASIS, by SUNY-Geneseo.

Based at Rice University, provides peer-review textbooks, primary at the introductory level.

Searches a number of the large OER databases, including OER Commons and Open Textbook Library.

"A Massively Collaborative Open U.S. History Textbook."

Peer-populated platform, contains lesson plans, video introductions to museums, images, and classroom activities.

British Columbia has been doing a lot of innovative things with open textbooks. Browse their list of authored textbooks.

A free online calculus from the Five College Calculus Project. Also has Advanced Calculus and The Geometry of Spacetime.

Open textbooks and other material for legal studies at the undergraduate and graduate level, as well as some resources for layperson legal research.

A repository of links to freely available texts that replace a traditional reader for Composition courses, from the library at Columbus State Community College (Ohio).

A nonprofit organization making open-source textbooks in economics.

Open textbooks and other resources from the City University of New York.

Open access books from academic publishers.

Open textbooks from Ontario colleges and universities.

Open publishing platform that specializes mostly in books for education and the social sciences.

Open textbooks produced by and used in the University System of Georgia.

Open resources for chemistry, biology, physics, mathematics, and computer science.

Open access books in science, technology, and medicine.

Open books and other resources on user experience.

Open textbooks and other classroom material. Leans heavily towards STEM topics.

One of several open textbooks made available by the College of Lake County, Illinois.

Stand-along teaching or learning modules covering health professions education, provided by the Association of American Medical Colleges in partnership with the American Dental Education Association and the American Psychological Association.

Free, open source, online course management system for mathematics and other quantitative fields. Students can do practice sessions on their own, or faculty can integrate the textbooks and exercises into a course.

Open and free online platform for computational education, research, and collaboration in nanotechnology, materials science, and related fields.

Open textbooks, course shells, and more from faculty at Linn-Benton Community College in Oregon. Some overlap with Open Oregon.

Textbooks and other course materials, heavy on math, science, music, and North Dakota history.

Platform for both browsing and authoring OER.

Open textbooks from UMass-Amherst.

Open textbooks and links to online materials in Geography.

A listing of low- and no-cost course materials used by college and universities in Oregon.

Open textbooks from faculty at the University of Saskatchewan.

Open Psychology 101 resources from the University of Maryland.

Project funded by a $2.5 million dollar grant from the Department of Education to create open Nursing Textbooks with open simulations.

Open textbooks and open access scholarly books in Social Work.

Open textbooks from faculty in the SUNY system, arranged by subject.

"All textbooks are either used at multiple higher educational institutions, or affiliated with an institution, scholarly society, or professional organization." Maintained by the University of Minnesota.

Open textbooks in mathematics.

Open textbooks from WhatCom Community College (Washington State). Heavy on medical and health care topics.

OER materials, arranged by discipline, used in courses offered at California Community Colleges.

Open textbooks from faculty at Virginia Tech.

OER from faculty in PA.

More OER from faculty in PA.

Directory of OERs written/published through Pressbooks, an open authoring platform.

Open teaching materials for Biology.

Zero-textbook cost textbooks from the College of the Canyons (California) on a wide variety of topics.