These links lead to openly available, free, no-instructor, no-credit courses created and hosted online by universities, educational organizations, and companies.
Open Course Labs
MyOpenMath https://www.myopenmath.com/
WeBWork (WeBWorK is an open-source online homework system for math and sciences courses) http://webwork.maa.org/
Open Intro (Statistics Labs) https://www.openintro.org/index.php
University sponsored open courseware
MIT Open Courseware http://ocw.mit.edu/index.htm
Carnegie Mellon University http://oli.cmu.edu/learn-with-oli/see-our-free-open-courses/
Notre Dame OpenCourseWare http://ocw.nd.edu/
Open Yale Courses http://oyc.yale.edu/
Stanford Online http://online.stanford.edu
Tufts OpenCourseWare http://ocw.tufts.edu
Utah State OpenCourseWare http://ocw.usu.edu
Educational Organization sponsored open courseware
CosmoLearning http://www.cosmolearning.com/
Curriki http://www.curriki.org/
National Repository of Online Courses http://www.montereyinstitute.org/nroc/
Open Courseware Library http://opencourselibrary.org
OpenCourseWare data faceted search http://serendipity.utpl.edu.ec
OpenCourseWare Consortium http://www.ocwconsortium.org/
Peer 2 Peer University (P2PU) https://p2pu.org/en
Saylor.org Academy http://www.saylor.org
Sofia http://sofia.fhda.edu/
