Antispam Bee
Antispam plugin with a sophisticated tool set for effective day to day comment and trackback spam-fighting. Build with data protection and privacy in …
DoFollow Case by Case allows you to selectively apply dofollow to comments and make links in pages or posts "nofollow".
Easiest plugin to disable/remove comments from complete site.
MP Spam Be Gone is the simplest, most effective Spam blocker.
Delete all pending comments from your database easily.
Slider CAPTCHA is a WordPress plugin that will allow you to replace or add a CAPTCHA field to any WordPress form.