Part 1 of the Essential Extensions can be found here. Below are 5 more useful Chrome extensions as a primary school teacher you may want to take a look at:
Similar to Checker Plus for Gmail this is a handy extension to add to your browser. Now you can easily search your Drive contents at the click of a button, in a clean, uncluttered window.
A very useful extension that enhances your experience of using Google Classroom. Access all your classes from the browser bar and share websites at the click of a button. Enables you to perform all the standard tasks (question, assignment, announcement) quickly too.
A neat way of finding all your bookmarks, with the classic 'Google' look - and you have the option of searching through them all too -useful if they're as disorganised as mine...
Search your Google Drive contents from the omnibox (browser bar) in Chrome by typing 'dr' followed by [Tab] - a great time-saver.
Keeps everything you have copied or cut to your clipboard and enables you to roll-back to any item. Report-writing season? Of course you would never use copy and paste for these, but in theory....