A simple plugin to add few enhancements when checking a row on default Admin Tables, such as Users, Plugins or Posts lists.
A carrot a day keeps the developer away.
Just another DD UI. Change all checkboxes in the admin panel to switches.
Collapse and reduce the height of hierarchical category and taxonomy panels in the WordPress admin (not needed for WordPress 3.5+).
Create to-do lists on your posts and pages similar to those used in Basecamp and Backpack.