GetNotify - GetNotify is a free email tracking software solution.
Bananatag - Find out what happens to your emails after you press send! Add email tracking, attachment tracking, email scheduling and templates to your daily emails.
Mailtrack.io - The best email tracking solution I've found. Free
iTrackmail - Want to know if people are reading the emails you send?
Intelliverse Email Tracker - Intelliverse Email Tracker provides insights to increase the productivity of your emails.
ClickNotifi - With ClickNotifi you get notified when the customer visits website from your email so you can call...