this is "an easy-to-use online platform for the construction, customization, and dissemination of open educational resources (OER)..."

Textbooks, courses, videos, and more are listed here in an easily searchable page.

These Texts have a traditional copyright but are free to use for educational purposes with registration.

Created by ISKME, the Institute for the Study of Knowledge Management in Education

This ACRL list of textbooks is aimed at courses for teacher candidates.