EmailTracker.cc - Free Email Tracker for Gmail. Close More Deals with Comprehensive Email Tracking, Automated Follow-up Reminders, and Detailed Click Insights
Followup.cc - FollowUp for email is a lightweight productivity suite that keeps your conversations and tasks from slipping through the cracks. Set perfectly timed reminders that arrive at the top of your inbox, right when you need them.
Spark Mail - Spark helps you take your inbox under control. Instantly see what’s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues
Gmelius - Gmelius is the first collaboration platform designed for G Suite and your company's daily tools.
MailTime - Go through your email as fast and easy as text-messaging
Boomerang for Outlook - Boomerang for Outlook offers email productivity tools to track, schedule and send mails at the right time.