Apervita - Apervita is a self-service platform that allows health enterprises and professionals to author evidence-based insight and connect it to practice, anywhere.
MailTracker - MailTracker is a mobile email tracking solution.
Support Hero - Educate your customers through self-help support
Mailtrack.io - The best email tracking solution I've found. Free
HelpSite - HelpSite is a simple service to help your setup the perfect support centre or help site.
Hunter - Find all the email addresses related to a domain