linkedbinary900

Adds an option to the “Edit Post” screen, allowing the user to easily choose another post to edit by clicking a link to that post’s edit screen.

Jump to – Post Edit

Gives the "Edit Post" screen the ability to jump from one post to another.

robfelty

Category reminder uses javascript to assert that a category has been assigned 
to a post before publishing it. If no category is assigned, then it will 
prompt the user to assign before publishing.

Category Reminder

This plugin requires users to assign a category to each post other than "Uncategorized".

Jump to – Post Edit vs Category Reminder