WP XHProf Profiler

This plugin will give you the total number of queries to the db per page, as well as the total time it took to render those queries out to the page.

Cross-Plugin Debug & Trace Recorder - Records and visualizes hook execution order for WordPress developers.

Profile your WordPress admin performance. Identify slow plugins, database queries, hook execution times, and memory usage from one clean dashboard.

See which blocks load which CSS/JS assets on a page and estimate their weight.

Find and fix what slows your WordPress site. Real-time performance monitoring, plugin profiling, and external request tracking.

Gravity Forms Add On. Adds custom tabindex field to the "Advanced" tab for form fields.

This plugin shows on the Dashboard the Technorati Reactions of your blog. It is a widget for the dashboard

Allows forcing users to register and login individually on each post or page.

This plugin for WordPress will give up to four personalized messages depending on the origin of the visitors of your blog.

Allows you to insert Karmacracy links into posts or pages and share your posts on Facebook and Twitter.