Gmail is one of the most popular free Email service from Google. Gmail has a feature call Gmail labs, using it you can add many new features to your Gmail account. You can access Gmail lab under Setting -> Labs.
If you will enable at least one of the lab then a shortcut will create at the top right corner as shown below:
As if Gmail wasn’t powerful enough, you can find all sorts of goodies and extra features in Gmail Labs. The list is pretty massive, so I’ve narrowed down to 10 favourite labs to help increase your email productivity.