WP-Markdown
Enables the popular Markdown syntax in your post editor for posts, pages, and custom post types, with a help bar to guide you along.
Responsible
Test your WordPress site's responsive design across a number of device sizes, with a bookmarklet in your admin toolbar.
Timespan
Add an approximate reading time for your WordPress posts to the top or bottom of the page, so users will know how long it will take them.
Autoptimize
Takes all of the CSS and JavaScript files loaded by plugins and themes, and combines them into one file to make your site quicker.
Google Pagespeed Insights
View pagespeed analytics right in the WordPress admin, and run automated tests to check every page on your site
Revisr
Manage Git repositories right from the WordPress admin. Commit changes, add branches, backup your database and rollback in a visual interface.
PressForward
Automatically pull in content from RSS feeds and around the web, then discuss them with your team and draft new posts from new ideas.
List Category Posts
Add posts from a category to any post or page right in the post editor using an included shortcode or widget. Lots of options and customizations.
Google Docs to WordPress
A chrome extension to draft your posts as a Google Doc then automatically send it over to WordPress as a post draft to publish.
Remote Media Libraries
Automatically add media from services like Vimeo, YouTube and Flickr to WordPress posts using the media uploader.
Show/Hide Content at Set Time
Use a shortcode included in the plugin to automatically display or hide content on your posts and pages according to the time and date.
WP Couch Mode
Add a distraction-free reading mode to any post or page, allowing users to view your main content in a fullscreen.