GetNotify - GetNotify is a free email tracking software solution.
ClickNotifi - With ClickNotifi you get notified when the customer visits website from your email so you can call...
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.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Mailtrack.io - The best email tracking solution I've found. Free
Intelliverse Email Tracker - Intelliverse Email Tracker provides insights to increase the productivity of your emails.