New for fourth grade: 
https://app.studiesweekly.com/online/
Username and password will be e-mailed

Clever (Benchmark Universe is here, with books to read)
https://clever.com/

The Public Library
https://www.pwcgov.org/government/dept/library/Pages/default.aspx

 Imagine Learning
https://app.imaginelearning.com

SOL Pass
www.solpass.org

Readworks -- https://www.readworks.org/

News E.L.A. -- www.newsela.com

Wonderopolis -- www.wonderopolis.org

Epic -- www.getepic.com

Also try the home learning link at the top of the Vaughan home page and these PWCS recommendations
https://www.pwcs.edu/departments/Instructional_technology/learning_materials