url.0spam.org URL Black List | This list contains the IP address of domains found to be in the source of spam emails found in our traps.
return codes not very clear
http://dnsbl.tornevall.org/
+ https://www.tornevall.net/
+ related to https://www.fraudbl.org/
+ seems a bit unstructured and not very well documented
+ seems active
http://dronebl.org/
http://mailspike.net/usage.html
http://psbl.org/