Polymail - Native email app for email productivity.
Sortd - Rated the #1 App for Gmail
Airmail for iOS - One of the best Mac email clients, now on iPhone
Drag for Gmail - Transform Gmail into organized To Do lists (like Trello)
Airmail - Airmail is a lightweight and lightning fast mail client for Mac.
Get My Receipts by cloudHQ - Organize your receipts in one click