Beautifier provides several options to clean up WP's messy (X)HTML source code output, such as code indentation.
Description: A filter for the FeedWordPress content syndication plugin.
Remove overhead from the HTML, speed up your website and disable widgets you don't use
This plugin strips the country code from links to releases on the iTunes Music Store
WPSSO extension to remove outdated Schema Microdata, leaving the superior Schema JSON-LD markup untouched for Google.
Add an admin strip to your WP 2.1.x blog - based on an idea by Matthew M tweaked by Brendan Borlaise.
CommentSafe is a very simple plugin which removes (X)HTML tags you specify from your comments.