SpamAssassin - Use this program to "Unspam" your mailbox(es).
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...
Brevo - Innovative online Email Marketing solution to manage your contacts, create & send your newsletters and track your results. More than 80 000 clients. Best prices and attractive features.
Oikik Antispam - Oikik is a cloud-based email filtering service that works with your existing email service.
Campaign Monitor - Email marketing software built for designers and their clients to run successful email campaigns.