Laytr is described as 'is the easiest way to defer emails. It lets you schedule outgoing correspondence, snooze incoming e-mail and set reminders of important messages' and is an website in the Office & Productivity category. There are more than 10 alternatives to Laytr, not only websites but also apps for a variety of platforms, including Gmail, Google Chrome, Sparrow and Mail Pilot. The best alternative is FollowUpThen, which is free. Other great sites and apps similar to Laytr are NudgeMail (Free), Boomerang (Freemium), Vocus.io (Paid) and NotNow.co (Free).
Rebump sends friendly follow-up messages to your email recipients for you. These automated emails are customized to appear as if you sent the email yourself. You can track and analyze all of your follow-up emails with your Rebump account.
Mailreminder.net is the product of some of my own frustations with trying to remember stuff during the day. I have tried numerous todo list apps and websites to keep up with requests that end on my inbox.