Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
Ditto - Easy to use interface; Search and paste previous copy entries; Keep multiple computer's clipboards in sync; Data is encrypted when sent over the network; Accessed from tray icon or global hot key; Select entry by double click, enter key or drag drop…
Geary - Geary is an email application built for GNOME 3.
Maccy - Lightweight open-source clipboard manager for macOS
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.
ClipboardFusion - ClipboardFusion makes it easy to remove clipboard text formatting, replace clipboard text or run powerful macros on your clipboard contents! You can even sync your clipboard with other computers an...