You can review any product or service that you have used in a school. You are only limited by your imagination 😉.
Some ideas of who or what to review
You can review anybody (e.g. the company that set up your WiFi, the pool cleaning company, your stationary provider, the security company that manages your access control, etc.) or anything (e.g. the ebooks you use, tablets rolled out in your classroom, interactive whiteboards, lawnmowers, etc.).
Reviews are what keep suppliers accountable and help schools discover the most reputable and top-rated suppliers out there. By writing a review, you are helping other schools make better purchasing decisions.
I hope I have inspired you to write your first review 🙂.