Mailspring - Mailspring is a mail client for Mac, Windows and Linux.
ezgif.com - Ezgif.com is simple online gif maker and toolset for basic animated gif editing.
Geary - Geary is an email application built for GNOME 3.
Instagiffer - Create GIFs from anything!
Airmail - Airmail is a lightweight and lightning fast mail client for Mac.
Gifsicle - Gifsicle is a powerful, simple command line tool for creating, editing, and optimizing animated GIFs.