1. Unsubscriber for Gmail (free, iOS) is the quickest way to unsubscribe from newsletters and mailing lists.
The app will scan your Gmail account for any email lists you may be signed up for. All you need to do is swipe left to unsubscribe and swipe right to stay subscribed. It's a super-quick and easy way to clean up your inbox!
If you don't have an iPhone, scroll down to "Websites and Skins" for a browser-friendly unsubscriber!
No, it's not the Gmail app – it's Outlook, which has a slick new interface thanks to Microsoft's acquisition of Acompli.
With one swipe, you can archive, delete, or schedule an email to show up at a later time. With one tap, you can add an attachment from Dropbox, Google Drive, or OneDrive. Outlook's killer feature, however, is that you can view your Google Calendar and Google Drive (or OneDrive or Box) files without ever leaving the app.
10. The Gmail Menu extension for Safari gives you a shortcut for emailing links.
If you email links often, consider getting this Safari extension, which adds a "Gmail" shortcut to the right-click (or control + click) menu on Mac. You can select "Gmail" on any page to open a new tab or window with an email already composed. The subject is the page title and the body is the URL.