Warmup Inbox - Warmup Inbox is a tool that automates the process of warming up your email inboxes, raising your sender reputation and inbox health automatically.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
MailReach.co - The #1 email warming service to improve your deliverability by generating realistic and meaningful engagement to your emails. Easy-to-use solution to help you land in the main inbox instead of the spam folder.
Geary - Geary is an email application built for GNOME 3.
Warmbox.ai - Warm up your cold email inbox, and never land in spam anymore!
Evolution - Apps/Evolution - GNOME Wiki!