Here is a list of websites I had saved from Reddit about 8 years ago. Apologies in advance, I haven't checked any of the URLs if they are still valid.

OP

hitching a ride to add on various study helps. free online education dump incoming:

http://education-portal.com/academy/course/index.html

http://101science.com/

https://iversity.org/

http://www.openculture.com/freeonlinecourses

https://www.coursera.org/

https://www.edx.org/course-list

http://www.dliflc.edu/products.html use the GLOSS link

http://www.coursehero.com/subjects/

http://oli.cmu.edu/

http://ocw.mit.edu/courses/find-by-topic/

http://www.saylor.org/

http://ocw.jhsph.edu/

http://www.open.edu/openlearn/

http://ocw.tufts.edu/

https://itunes.stanford.edu/content/rss.html

http://webcast.berkeley.edu/#

http://www.makeuseof.com/tag/3-websites-started-learning-programming-language/

https://www.futurelearn.com/

http://www.flashcardmachine.com/ You can use flashcards made by other users. Whether you trust them is up to you

http://freerice.com/category It quizzes you on the basics of a subject o your choosing, and donates rice for each answer you get right once you turn off adblock

http://openstaxcollege.org/

http://justenglish.me/2012/09/01/free-books-100-legal-sites-to-download-literature/

http://blog.boundless.com/2013/04/the-cost-of-textbooks-is-too-damn-high-so-boundless-made-free-ones/

http://freescience.info/index.php

To the best of my knowledge, these are all free and legal, and of varying degrees of usefulness. here's the thread I originally put it in, which may have some similar stuff. http://www.reddit.com/r/AskReddit/comments/268a0s/what_random_things_can_i_get_certified_for_over/