Mail Checker Plus is a Google Chrome extension that helps you manage your Gmail and/or Google Apps mail. It is top-rated, highly customizable and integrates seamlessly into your browsing experience. You can even read or delete them without opening your Gmail account.
Right Inbox is an extension for Chrome and Firefox that works with your Gmail account to schedule emails for sending later, much like previously mentioned Boomerang, but free and simpler. Right Inbox is free application to schedule email in Gmail like never before.
CopyPasteCharacter.com is a web and iPhone application for copying the ‘hidden’ characters that comes with the computer’s typefaces, to be pasted into emails, tweets, text documents, forums and whatever else you might need to spice up with an extra.
GMail Drive creates a virtual filesystem around your Google Mail account, allowing Gmail as a storage medium. It enables you to save and retrieve files stored on your Gmail account directly from inside Windows Explorer. It literally add new drive to your computer under My Computer folder
Mingly is a relationship management tool, it has plug-in for Gmail in Firefox and Chrome. It brings messages and key updates from LinkedIn, Facebook and Twitter to Gmail, so you can keep track of who and what’s important. It shows a feed of contacts and important events
