水野史土

This plugin shows the list of the categories of your blog. When you click one of the categories, you will jump to post-new.php, where the category you clicked is selected.
Usually you go to post-new.php and write a post, then you select the category of the new post. This flow may result in publishing without selecting any category. In such cases, the post is categorized as ‘Uncategorized’ and you have to select a category after publishing.
This plugin solves this problem. You can select one category before writing a post, no more unwanted Uncategorized.
<a href="http://plugin.php-web.net/wp/category-select" rel="nofollow ugc">Japanese description</a> is also available.

Select Category to Post

Category names are shown on your dashboard with a hyperlink, and when you click one, you will go to post-new.php, with the category already selected.

Marzio Carro

Adds categories and tags functionality for your pages.
This plugin addsthe ‘post_tag’ and the ‘category’ taxonomies, which are the names of the existing taxonomies used for tags and categories the Post type ‘page’.
This enables the categories metabox and the tags metabox in the New or Edit Page interface.
The plugin has no settings, does not alter the database and only uses hooks to 
achieve it’s goal. It works perfectly fine with Multisite installations.
This plugin WILL NOT add any display of categories or tags to your template files.
Plugin’s website: <a href="http://technotes.marziocarro.com/category/wordpress-plugins/" rel="nofollow ugc">http://technotes.marziocarro.com/category/wordpress-plugins/</a>
Author’s website: <a href="http://technotes.marziocarro.com/" rel="nofollow ugc">http://technotes.marziocarro.com/</a>

Category Tag Pages

Wonderful functionality

Yes, it works. Uses very few lines of code and it's a simple and safe solution to have categories and tags in pages.

It works

Adds categories and tags functionality for your pages.

Select Category to Post vs Category Tag Pages