Sifting through the thousands of options in the Chrome Web Store can be daunting, so here's a list of the ones that I have used over the past few years that I think are worth exploring right away (note that the descriptions are, for the most part, directly from what was provided in the Web Store):
Google Chrome Apps:
Apps are web applications that run on the Google Chrome Browser. When you use a Chromebook, they appear in the "All Apps" icon when you hit the Launcher button (the little magnifying glass in the lower left corner), so they are almost like the "Programs" that you might be used to with a Windows-based system. Lots of apps are already available when you sign in to a Chromebook, especially if you are a GAFE (Google Apps for Education) school. You can pin apps to the "Shelf" (i.e. Taskbar) by right-clicking (that's done by two-finger clicking on the touchpad of the Chromebook) on the icon you want to pin. Start by pinning Google Classroom and Google Drive - you'll access them a lot.
Apps to add to your collection (via the Chrome Web Store):
Google Keep - Quickly capture what's on your mind and share those thoughts with friends and family. Speak a voice memo on the go and have it automatically transcribed. Grab a photo of a poster, receipt or document and easily organize or find it later in search.
Padlet - Padlet is the easiest way to create and collaborate in the world. It works like a sheet of paper where you can put anything (images, videos, documents, text) anywhere, from any device (pcs, tablets, phones), together with anyone.
PowToon - PowToon lets you create awesome presentations and animated videos - it's like a hybrid between a slideshow and a video, with a great drag-and-drop interface. Students love creating and animating with this app; teachers love the ability to create dynamic presentations.
EDpuzzle - EDpuzzle empowers teachers to make any video your lesson. Crop a video, explain it with your own voice and embed quizzes at any time. Take any video from YouTube, Khan Academy, Learn Zillion, etc. make it perfect for your classroom and more engaging for your students. Make any video a true lesson by making it to the point, personal and effective, plus get all the data about your students so you know if they truly understand the lesson.
Pear Deck (as well as Socrative and Nearpod which have very similar features) - Interactive presentations and formative assessments to engage every student in your room, every day! Plan and build interactive presentation deck directly from your Google Drive. Launch a live, interactive session on the projector. Every Single Learner joins the live session on his or her device and participates.
Remind - Remind offers teachers a free, safe and simple way to instantly text students and parents. Teachers can send or schedule reminders, assignments, homework, assessments, or motivational messages directly to students' and parents' phones. Interactions are safe because phone numbers are kept private, and messages are sent with no open replies.
Google Chrome Extensions:
Extensions help you configure the Chrome browser itself. They can again be accessed through the Chrome Web Store, and when added will appear as small icons in the upper-right corner of the browser. Extensions are designed to modify and enhance the functionality of using Chrome. You are also likely to run across links to add extensions from websites that you frequently use (Pinterest, for example, has an extension).
Extensions to add to your collection:
Share to Classroom - Get your class on the same (web) page, instantly. Web Page Sender allows users of Google Classroom to collaborate in realtime. Teachers can "fling" or share urls with students, and students can fling urls to teachers.
Save to Google Drive - The Save to Google Drive Chrome extension helps you save web content or browser screenshots to your Google Drive.
Readability - Readability is a web and mobile app that zaps clutter and saves web articles in a comfortable reading view... provides a better way to read online, turning any web page into a comfortable reading view right in your web browser.
Google Drive Add-ons:
Add-ons are tools built by third-party developers to enhance the functionality of Google Drive tools (Docs, Sheets, Forms, etc.). Unlike apps and extensions, you don't access them through the web store. Instead, they can be searched by clicking the Add-ons menu button from whatever Google tool you are using. Choose "Get add-ons" to search for what you want to add. Each one comes with options and help instructions once they are added. If you find yourself thinking "I wish Google Docs did [insert some advanced function from Microsoft Office]..." chances are there is an add-on to help.
Easy Bib - Automatic bibliography citation generatorSorted Paragraphs - Sort your paragraphs, lists, bibliography and individual table rows or columns in either alphabetical or reverse alphabetical order.g(Math) - Create graphs of functions and inequalities (including plotting points and finding the line of best fit) and write complex math in the sidebar & insert it directly into your document.MindMeister - Turn any bullet-point list into a visually appealing mind-map and insert it directly into your Google Doc.
Save as Doc (for Google Sheets) - Convert any Google Sheets spreadsheet into a Google Document for improved legibility of lengthy cell text entered manually or through a Google Form submission. Basically, this will make Google Forms submissions readable!