A Firefox browser extension that allows you to quickly check for new mail in your Google Mail and Google Apps accounts.

Store every conversation, email, call, meeting, document, and deal you’ve ever had with a contact. You’ll always know who you talked to, what was said, and when to follow-up next.

• $29/mo
• $49/mo
• $99/mo

A plugin for the Chrome and Firefox browsers that helps you clean out your inbox, transform emails into trackable actions, group them into manageable projects and keep an eye on important emails.

• Free
• $24.95/yr

This plugin for Chrome, Safari and Firefox turns organizing your Gmail account into a competitive game. You earn points for archiving and replying to emails, and can rank yourself with your friends.

Automatically pull contacts from Facebook, LinkedIn, Twitter and more, and add them to your Google Contacts. It can automatically turn an email address into a full contact, display contacts by company, view the contact's Facebook or Flickr page, and more.

• $9
• $19
• $39
• Commercial

A Firefox browser extension to manage multiple Gmail accounts and receive new mail notifications. It allows you to view account details including unread messages, saved drafts, spam messages, labels with new mail, space used, and new mail snippets.

An inbox organizer for Gmail and Yahoo! Mail that automatically moves messages into their appropriate folders, separates high and low priority emails, and summarizes low-priority emails in a daily digest.