Google Operating System: Hidden Labels in Gmail
Gmail has many other hidden labels that can make your life easier, so you don't have to use the advanced search:
* label:inbox - search only your Inbox. It's a good idea to keep your Inbox clean.
* label:star (label:starred) - search only your starred messages. You can use the star button like a bookmarking system. Star only important messages.
* label:draft (or label:drafts) - search only unfinished messages. Drafts could be used for storing notes or emails that must be sent later.
* label:sent (or label:sentmail, label:sent-mail, label:sent mail ) - search only sent mail. It may be useful to restrict your search only to messages you've sent, or only to messages you've received if you add a minus.
* label:all (or label:allmail, label:all-mail, label:all mail ) - search all your mail, including messages from Trash (label:trash) and Spam (label:spam).
* label:read and label:unread. Restrict your search only to read mail or unread mail. For example, to find all your sent messages that have unread replies, you can search for label:unread label:sent.
* label:voicemail (or label:voicemails ) - search only the voice mails received from a Google Talk User