Free Tools to Learn Anything
“Our mission to provide a world-class education for anyone, anywhere.” All Khan Academy content is available for free at http://www.khanacademy.org.
Knowmia — a crowdsourced video platform designed to help teachers find and create video lessons and content on many areas of study.www.knowmia.com
OpenEd is the largest K-12 educational resource library, offering over a million videos, games, assessments and exercises for every Common Core Math, Language Arts, Literacy and Next Generation Science standards. Teachers can create their own lessons and assessments using this content. Most of the content is free. https://www.opened.io/
An Open Education Resource (OER) for K-12 featuring curated STEM resources and Open Source textbooks. Teachers can make their own textbooks and remix others, assign practices and keep track of student progress.http://www.ck12.org/
Common Sense review here