Nicolas Marin Torres

With this plugin you will be able to take advantage of long tail keyword so you can learn more about your niche with Volume and CPC. 
This plugin helps you generate ideas for your post.

WP SEO Title

This SEO plugin offers keyword suggestions with Volume, CPC and Profit

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.

WP SEO Title vs WP Custom Category Meta