Remind - Messaging app where you can send/receive text messages without sharing phone numbers. You can send announcements to a class or group, or have conversations. You may attach files, and it links to Google Classroom.
Kahn Academy - Math, Science (Biology, Chemistry, Physics, Health (and anatomy resources), and more), History, Art History, Economics, Personal Finance, Growth Mindset, and lots more. All free and all accessible to our students. Syncs with Google Classroom. Video, practice, quizzes, explanatory articles.