Many more resources that teachers can also access are available on the "Student/Parent Resources" page, so please check that out as well if you are looking for ideas for your classes.
Google has created a site designed to help teachers use various G Suite tools to teach from home.
This link to the OER Commons provides access to a wide variety of learning resources, including lesson plans and several online learning sites.
Khan Academy has hundreds of videos for students of all levels, though it is probably most useful to students in grades 5-12. These include videos on various math topics (with example problems), science, history, standardized test prep, and more. Many teachers are already using Khan Academy in conjunction with Google Classroom. Users do not have to sign in to watch the videos (just search for the topic that you want to study), but students can log in with their school Google account and their progress will be saved.
Readworks is a great site with hundreds of articles for K-12 students on a wide variety of topics (fiction and nonfiction) with question sets to assess student comprehension. They are easy to assign and grade via Google Classroom. Mrs. Hurtt uses this frequently and can help you out with any questions.
Common Sense Media has put together a number of resources that educators can use to help establish norms and expectations for distance learning and run and effective digital classroom.
Share My Lesson has tips and information on virtual learning as well as collections of resources that students can access at home to keep learning, which are organized by grade level.
Scholastic Learn at Home is a free website that provides students with 20 days' worth of exciting learning journeys carefully created by Scholastics' editors to span the content areas and keep your students actively engaged and challenged.
The public library in Paris, Illinois has some great online resources available, including TumbleBooks Library. This is a collection of animated talking picture books, read-alongs, ebooks, quizzes, lesson plans, and educational games which is used by thousands of schools and public libraries in over 100 countries across the world. Related sites TumbleMath, TeenBookCloud, and AudioBookCloud are also available (just scroll down the page).