The Generic ping plugin can be used to add a generic RPC ping service to your blog.
Category: "2.x & above"
The Basic Antispam Plugin provides basic antispam features like: allow anonymous comments, detect feedback duplicates, feedback sensitivity to links, apply rel="nofollow", block spam referers, check referers for URL and check trackbacks for our URL.
The Wacko is a simple renderer plugin that provides Wacko style formatting. This allows to easily create different markup/formatting, even on blogs that do not allow HTML.