Learn how you can use Gmail more efficiently with these powerful search keywords File Name Extension Search Search "filename:doc" without quotes will display all document attached email's Search "filename:jpg" without quotes will display all Image attached email's Search "filename:ppt" without quotes will display all presentation attached email's Search "filename:pdf" without quotes will display all PDF attached email's Attachment Search Search "has:attachment" without quotes will display all email with attachments Google Circle Search Search "has:circle" without quotes will display all your friends email who are in your google plus circles From User Search Search "from:(user1@gmail.com)" without quotes will display all email from the user Search "from:(user1@gmail.com,user2,user3...)" without quotes will display all mentioned user's email (Starred Email) Searc...