Most OER textbooks can be fully downloaded immediately. In addition, depending on the Creative Commons license, they can be revised or remixed depending on the needs of your classroom. 

• LibreTexts offers textbooks in Biology, Business, Chemistry, engineering, Español, Geosciences, Humanities, K12 Education, Mathematics, Medicine, Physics, Social Sciences, Statistics, and Workforce.

• OpenStax offers a variety of OER textbooks that are written by professionals who are experts on each particular field. All textbooks require a rigorous standard of acceptance and require a peer-review process.

• PressBooks offers over 3,500 textbooks on a variety of subjects.

• Milne Open Textbooks are typically authored and peer-reviewed by SUNY faculty and staff. This is a good resource for niche subjects and/or topics.

• Open Textbook Library has over 1,000 open textbooks that are often reviewed by faculty in those respected subjects. Subjects include business, computer science, humanities, education, engineering, law, math, sciences, social sciences, student success, etc.

• FlatWorld requires a fee to use their textbooks, but since all of the material is developed using OER, the price to use the textbook is very low-cost. A purchase of the textbook also comes with additional features like "instructor supplements, included homework system, and an easy-to-use customization platform."

• The American Yawp offers a free and online, collaboratively built, open American history textbook designed for college-level history courses.

• PDXScholar has a small but unique collection of OER Textbooks used by Portland State University. Be sure to also check out their homepage for more open materials. 

Open Courseware, or OCW, is fully designed courses that are free or at a low-cost towards the public via the internet. 

• MIT Open Courseware has a vast collection of courseware to choose from. Be sure to use the filters on the left-hand side to narrow down the material.

• Open Learning Initiative offers a variety of courses at affordable rates since they are designed using OER. Courses are priced per student and are typically at $25.

• Lumen is a paid service, but since its courseware is designed with OER, the cost is low. Its additional features like Waymaker and Online Homework Manager are additional benefits.

• Cornell ECE Open Courseware offers courseware particularly for Electrical and Computer Engineering

• CogBooks is a paid service that uses OER to keep its cost low. It offers full courses in Agricultural Science, Business, History, Psychology, etc...

• Open Yale Courses provides video lectures, notes, labs, and more for a variety of courses which were previously taught at the university.