Annoyingly adds "Hello World" every post created!

This plugin will highlight keywords you specify on the admin moderation page, making it easier to spot manual spam and/or troll comments. It will also highlight duplicate comments that people spam on multiple pages.

FeenBan is a WordPress plugin for shadowbanning / hellbanning commenters.

MarkTroll is a WordPress plugin that will let you shadowban (hellban) any unlogged (regular) commenter on your blog.

A plugin to automatically moderate messages in six different languages and block those that contain hateful, degrading, or slanderous language.

Plugin to encode/decode and display content using the ROT13 cipher.