SpamCop - Beware of cheap imitations! SpamCop has been protecting the internet community since 1998.
AbuseIPDB - AbuseIPDB is an IP address blacklist for webmasters and sysadmins to report IP addresses engaging in abusive behavior on their networks, or check the report history of any IP.
StopForumSpam - StopForumSpam - a database of known forum and blog spam, its sources and the email addresses reported
NetCut - NetCut is a Software that helps you admin your network by purely on ARP protocol.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
Akismet - Akismet is a spam fighting service that protects millions of WordPress sites from comment and contact form spam.