HTML Purified
by John Godley on WordPress.org

Main options page allowing specific HTML tags
HTML Purified replaces the default WordPress comments filters with HTML Purifier, a super HTML filtering
library.
HTML Purifier is a standards-compliant HTML filter library written in PHP. HTML Purifier will
not only remove all malicious code (better known as XSS) with a thoroughly audited, secure yet
permissive whitelist, it will also make sure your documents are standards compliant, something
only achievable with a comprehensive knowledge of W3C’s specifications.
An additional feature of HTML Purifier is that it will produce valid well-formed XHTML code, something
which KSES does not do.
Features:
- Configurable KSES or HTML Purifier
 - Configurable list of HTML elements and attributes for both KSES and HTML purifier
 - Additionally process comments with HTML Tidy
 - URL blacklist
 - Fully localized (and awaiting translations)
 - Automatically escape PHP or anything inside backticks
 
HTML Purifier is available in:
- English
 - Spanish, thanks to José Cuesta
 - Belorussian, thanks to Marcis Gasuns
 - Russian, thanks to Ilyuha
 - Uzbekistan, thanks to Alexandra Bolshova
 - Dutch, thanks to Pieter
 - German, thanks to Andreas Beraz
 - Polish, thanks to Kasia Ciszewski & Dawid Śpiechowicz
 - Romanian, thanks to Alina @ InboxTranslations.com
 - Lithuanian, thanks to Nata Strazda
 - Ukranian, thanks to Iflexion Design
 
Documentation
Full documentation can be found on the HTML Purified page.