Open Knowledge

Directory of Open Access Journals (DOAJ), an online directory that indexes and provides access to high quality, open access, peer-reviewed journals at https://doaj.org/

Free ebooks by Project Gutenberg at https://www.gutenberg.org/

Google Scholar at https://scholar.google.co.in/

Internet Archive is a non-profit library of millions of free books, movies, software, music, and more at https://archive.org/index.php

Project MUSE: Online database of more than 200 journals from nonprofit publishers at https://muse.jhu.edu/

Shodhganga: a reservoir of Indian Theses at http://shodhganga.inflibnet.ac.in/

The Directory of Open Access Repositories – OpenDOAR at http://www.opendoar.org/

NPTEL – https://onlinecourses.nptel.ac.in/explorer

NATIONAL DIGITAL LIBRARY – https://ndl.iitkgp.ac.in/

SWYAM – https://swayam.gov.in

IGNOU – http://egyankosh.ac.in/

WIKIPEDIA

COURSERA.COM