WP-NMC is a full page cache plugin for WordPress in pre-release alpha state. It can use APC or a memcached server as backend.

Yet anoter gallery plugin for WordPress. Supports WordPress attachments or Flickr sets as gallery, has it’s on cache and based on Galleriffic. My own portfolio (link above) is provided by this plugin as well.

Adds a shortcut function to WordPress to create Slides JS slideshow from posts of a category.

Open Graph Headers can extend any WordPress theme with open graph headers.
The plugins extends wp_head() and language_attributes() functions.