An indispensable resource I have been using for 3 years now. I administer various assessments and assignments and receive instantaneous feedback, scores, and graphs. I would be remiss to say this revolutionized my teaching style. My questions are in the form of CAASP and aligned with the Next Generation science standards.
If you want quality resources and want to save time scouring the internet, look no further. You'll also be supporting your fellow teachers. You can find materials for most subjects, and these are modifiable as well. I have never regretted a purchase to date.
High quality videos on math, science, history, etcetera. Practice problems are embedded as well. This service is free and easily connects to google classroom. Serves as a great refresher for students who need reviewing for a test.