Human Presence | Anti-Spam WordPress Plugin
Human Presence is the #1 anti-spam WordPress plugin for stopping comments and form spam.
Stop Spammers
Aggressive anti-spam plugin that eliminates comment spam, trackback spam, contact form spam, and registration spam. Protects against malicious attacks …
Stop Signup Spam
Check user registration info against the Stop Forum Spam database before allowing registration
How To Block WordPress Referral Spam - Penguin Initiatives
Referral spam can cause a lot of problems for you when trying to make sense of your Google Analytics...
CleanTalk. Spam prevent plugin « WordPress Plugins
Spam Free WordPress « WordPress Plugins
Registration Honeypot: A Simple WordPress Plugin to Combat Spam
Registration Honeypot « WordPress Plugins
Gravity Forms Zero Spam
Anti-spam by CleanTalk - No Captcha, no comments & registrations spam
Max power, all-in-one, premium anti-spam. No comments & registrations spam, no contact spam, protects any forms. Just install and forget spam.