Google introduced add-ons for Docs and Sheets in Google Drive. These are additional tools that help individuals and businesses who relies heavily on google documents and spreadsheets. (I, myself for example relies heavily on google spreadsheets. Numbers on Mac are too troublesome to share with colleagues and I’m lazy to install MS Office for Mac)
To browse through add-ons for Docs and Sheets, select Get add-ons in the Add-ons menu of any open document or spreadsheet. (Add-ons for spreadsheets are only available in the new Google Sheets). via Bring a little something extra to Docs and Sheets with add-ons
Many of these tools are free and I especially love the Merge by MailChimp. It allows you to send email directly from a Google Doc to email addresses stored in a Google Sheet.
So if you are into Google Docs and Sheets and is looking to further increase your productive with add-ons, be sure to check out the Lifehacker post – The Best Add-Ons for Google Drive.