sa-blacklist

sa-blacklist is a hand-checked list of over 10,000 spammer domains. It's formatted for Exim, Postfix, Privoxy, Qmail, Spamassassin, Squid, and Sendmail. Depending on the application, it can block or score either on the sender domain and/or the embedded URLs in the spam. It's also available as an RBL (a DNS-based lookup of spammer domains).