Google Sheets add-ons offer a range of time-saving features to enhance the app's functionality, including data gathering, formatting and visualizing data, manipulating data, and sharing and publishing data. The best Google Sheets add-ons can help automate tasks, such as retrieving data from external apps, exporting data as XML or JSON files, sending personalized emails, and turning spreadsheets into mobile apps. With a vast array of options available in the Google Marketplace, users can find the perfect add-on to suit their needs and streamline their spreadsheet management process.