The Ping-O-Matic plugin pings http://pingomatic.com/, from where your ping gets relayed to a set of most common ping services.
Adds a toolbar on top of the post editor for easy HTML tag inserting.
The Texturize Plugin will perform many text replacements according with their formar, standard and double quotes with typographic quotes were appropriate (?? to ""), for example.
The source code of this plugin is not available
The Transport optimizer plugin helps you saving bandwidth.
It supports ETag headers and GZip compression.