SendRecurring - SendRecurring allows you to setup, send, and maintain scheduled email reminders.
Onesheet CRM - The Simple CRM for Google Sheets
Recurrr - Send recurring emails
HubSpot - Grow Better With HubSpot: Software that's powerful, not overpowering. Seamlessly connect your data, teams, and customers on one CRM platform that grows with your business.
FollowUpThen - The simplest way to schedule an email reminder
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.