Edudemic’s list is from way back in 2015, but it’s worth a mention for the way it presents the websites for elementary teachers. They display home pages for key sites, and include an overview of the kinds of resources the site contains. For example, under Language Arts, they suggest the site Readwritethink: “Use this site when you have a very specific amount of time to fill. Readwritethink has ideas that range in length from five-minute writing prompts that can kick off an assignment to multi-week units. The calendar activities section is packed with ways to tie your reading and writing lessons to seasons, notable people, and multicultural holidays.”