Google's Account Switcher Extension
If you don't have a secondary account setup for a work or school account, you'll be forced to use Google's account switcher to switch to a different one. This can be frustrating, especially when you want to use a specific service, like Google Drive, but only for a limited amount of time.
This extension is perfect for situations like this. If you're just visiting a new place, for example, you can set your personal account as the default, and then you can simply use G-Switcher to switch to your school mail.
This extension has a few limitations. You can only switch between accounts on the web version of Google, and not on the mobile apps. It is also currently only compatible with Chrome and Firefox, and has no compatibility with other browsers.