Musilda

Allow you to add custom meta tags and title for category. 
In next version will be added other seo plugins support.

WP Custom Category Meta

Allow you to add custom meta tags and title for category.

francescovitt

A minimal and “ultra-light” plugin to remove “Category:” string form category title
Features
<ul>
<li>No options required</li>
</ul>
any feedback or suggestions are welcome.

No Category Title

Removes "Category:" string form category title

WP Custom Category Meta vs No Category Title