MailDrop - maildrop is a Mail delivery agent used by the Courier Mail Server. The maildrop MDA also includes filtering functionality. maildrop receives mail via stdin and delivers in both Maildir and mbox formats.

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.

InboxKitten - An open-source, disposable email service 💌

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.

Unroll.me - A cleaner inbox is just a click away! Unroll.Me gives you the tools you need to manage a cluttered mailbox full of pesky subscriptions emails.

Warmbox.ai - Warm up your cold email inbox, and never land in spam anymore!