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

DaganLev

huntlyc

Allows you to set global meta tags and customize on each individual page/post.
The plugin will generate the blog title and page title as default title tags if not specified otherwise.

Simple Meta Tags

Allows you to set global meta tags and customize on each individual page/post. Please Note: Does not support custom post types

WP SEO Title vs Simple Meta Tags