limelightdept

Optimize page load times with full page caching. Improves Google PageSpeed Insights by an average of +30%.
Cache Ultra recompiles your javascript and css, then “snapshots” your pages into fully cached static html files. Automatically renews your snapshots every 8 hours to handle WordPress form tokens and such.
Also provides lazy loading site-wide or page-by-page. 
You’ll have full control of page resources and how they’re loaded on a per page or post type basis.
Create custom cache to handle the unique scripting needs for your site.
This plugin leverages our powerful caching API.
For more information visit http://www.limelighttheme.com

Cache Ultra

Optimize page load times with full page caching. Improves Google PageSpeed Insights by an average of +30%.

neoslab

Powered Minifier allow you to reduce your page load and increase your performance by minifying your HTML source along with all the CSS and JS code present in your markup.
<h3>License</h3>
Good news, this plugin is free for everyone! Since it’s released under the GPL, you can use it free of charge on your personal or commercial site.

Powered Minifier

Honestly it's the best minifier plugin for Wordpress 

Simply Excellent

Reduce your page load by minifying your HTML source along with all the CSS and JS code present in your markup.

Cache Ultra vs Powered Minifier