GetNotify - GetNotify is a free email tracking software solution.
AkrutoSync - Sync your Outlook contacts, calendar, tasks and notes on your PC direct with your phone via Wi-Fi or a cellular network.Buy · FAQ · Contact Us · SupportPeople also askWhat is Akrutosync?
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.
DAVx5 - DAVx5 is a CalDAV/CardDAV management and sync app for Android.
Mailtrack.io - The best email tracking solution I've found. Free
EteSync - Secure, end-to-end encrypted and journaled personal information synchronization.