Postgrey might be a bit more popular than SpamSieve. We know about 3 links to it since March 2021 and only 3 links to SpamSieve. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
I’ve been using SpamSieve on my Mac, both on the Mail app on my user account and on Outlook on my wife’s. Source: about 1 year ago
However, to answer the question, there is a third party spam filtering app for MacOS called SpamSieve that does a great job of filtering spam from "ham" (e.g., good mail.) I use it for the ISP mail account that my wife and I share in order to keep us from going insane from the amount of spam that goes to that account - I have a Mac that runs 24/7 running Mail with spamsieve. Source: over 1 year ago
This is just a total workaround, but check out SpamSieve: https://c-command.com/spamsieve/. When I used Mail full time, I found its spam filtering to be pretty effective. Source: over 1 year ago
This is what mailinabox does (https://mailinabox.email/) to combat spam and it has worked remarkably well. In the few years I've been running my own mail server I have received ZERO spam in my inbox. For more info, the technique is called greylisting https://postgrey.schweikert.ch/. - Source: Hacker News / over 1 year ago
I've used Postgrey, for Postfix, and it's greatly reduced my spam. However, first emails from new folk are delayed a bit. https://postgrey.schweikert.ch/. - Source: Hacker News / almost 2 years ago
Not to be confused with the GreyList service for Postfix - Postgrey. Source: over 2 years ago
SpamAssassin - Use this program to "Unspam" your mailbox(es).
Spamihilator - The free Anti-Spam-Filter Spamihilator removes more than 98% of spam mails before they even get into your inbox.
Mailwasher - Over 8 million people use MailWasher as their spam filter
Spam Reader - Spam Reader is a free anti-spam add-on for Microsoft Outlook.
SPAMfighter - SPAMfighter and Microsoft have built the strongest and most effective anti spam filter for Outlook, Windows Live Mail, Outlook Express & Thunderbird
Spamfence.net - Professional e-mail security free for private use: With Spamfence.