Flow-e is a visualization layer on top of your Gmail or Outlook inbox. It provides an elegant Kanban-like workflow that's combined with the ideas behind Inbox Zero and GTD. Flow-e eliminates the need of external task management tools and transforms your inbox into a central To Do app.
Sortd - Rated the #1 App for Gmail
Workona - A better way to work in the browser.
KanbanMail - A Kanban board for your emails.
OneTab - Whenever you find yourself with too many tabs, click the OneTab icon to convert all of your tabs into a list. When you need to access the tabs again, you can either restore them individually or all at once.
Drag for Gmail - Transform Gmail into organized To Do lists (like Trello)
One Tab Group - One Tab Group is a Chrome extension alternative to OneTab/Session Buddy, that allows you to manage your tabs & tab groups in one place. One click to aggregate all tabs & tab groups into one session.