Open Textbooks: Affordable Learning GeorgiaBay College OERBCcampusBoundless (archive)California Open Online Library for Education (COOL4ED)CK-12LibreTextsMichigan Open Textbook Project (3-12)Open CultureOpenStaxMilne Open Textbooks (formally Open SUNY)Open Textbook LibrarySaylor AcademySiyavula (4-12)