Glympse - Glympse is the easy way to safely share your location in realtime. No sign-up needed.
Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
OwnTracks - Cross-platform location sharing
Geary - Geary is an email application built for GNOME 3.
Mapple.me - Mapple.me bridges the gap between available time and availability of friends to increase social...
The Bat - The Bat! is a secure desktop email client for Windows, designed to protect your correspondence against third-parties and to save your time.