Freshsales CRM - A full-fledged CRM for high-velocity sales teams.
SendRecurring - SendRecurring allows you to setup, send, and maintain scheduled email reminders.
Pipedrive - Sales pipeline software that gets you organized. Helps you focus on the right deals, so easy to use that salespeople just love it. Great for small teams.
FollowUpThen - The simplest way to schedule an email reminder
InStream CRM - Business relationship management platform - CRM alternative
LetterMeLater.com - LetterMeLater.com allows you to send emails to anyone, with the ability to have them sent at any future date and time you choose.