Boomerang for Gmail - Boomerang for Gmail is a Firefox / Chrome plugin that lets you take control of when you send and receive email messages.
FollowUpThen - The simplest way to schedule an email reminder
Right Inbox - Schedule Emails in Gmail To Be Sent Later
Everypixel - Stock Image Search Engine That Filters Out Trash. Made for designers who hate bad stock images.
Dashmote - Dashmote bundles stock image providers to make finding stock images as easy as possible.
Email Studio for Gmail - Send personalized emails, schedule emails directly in Gmail