chaozh

post switch was created to free you from the hell of switching post panel in your admin dashboard when you want to edit more than one post at a time.
This plugin adds a meta box in your post edit panel and will display all posts in the related category for choosing. Once selected, the post you are editing with will automaticaly changes to the chosen post.

Post Switch

Post Switch allows you to switch your editing post right in your admin post edit panel

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".

Post Switch vs Category Reminder