UC Berkeley Pressbooks Guidelines
https://berkeley.pressbooks.pub/guidelines/
Open Textbook Library
http://open.umn.edu/opentextbooks/
OASIS
https://oasis.geneseo.edu/index.php
OpenStax College
https://openstax.org/higher-ed
Open Textbook Project (BC Campus)
https://open.bccampus.ca/
IntechOpen
https://www.intechopen.com/
Directory of Open Access Books
https://www.doabooks.org/doab?uiLanguage=en
Open Oregon Resources
https://openoregon.org/resources/
Lyryx Learning
https://lyryx.com/
Bloomsbury Collections
https://www.bloomsburycollections.com/about/collections
Books - De Gruyter Publishers
https://www.degruyter.com/browse?authorCount=5&openAccess=true&pageSize=10&searchTitles=true&sort=datedescending&type_0=books
Open Access eBooks on JSTOR
http://about.jstor.org/open-access?cid=eml_jb_OA_10_2016
Milne Open Textbooks
httphttps://milneopentextbooks.org/
COOL4ED--Textbooks
https://www.cool4ed.org/findetextbooks
The Open/Alternative Textbook Initiative at Kansas State University
https://www.lib.k-state.edu/open-textbook
Textbook Equity
https://www.textbookequity.org/
Global Text Project
http://globaltext.terry.uga.edu/
Bookboon.com
http://bookboon.com/