Dana Ross

HTTP/2 is the new generation of the venerable HTTP protocol that powers the web. Among its most powerful features is server push, a way for web servers to send resources to the browser before it even realizes it needs them. This avoids the usual HTTP request/response cycle which happened for every script or stylesheet on a page.
This plugin enables WordPress to send a <code>Link:<...> rel="prefetch"</code> header for every enqueued script and style as WordPress outputs them into the page source. Unfortunately, it can’t help plugins and themes that output their scripts directly into the page itself, but these will continue to work as they always have.
Requires a web server that supports HTTP/2.
<h3>WordPress 4.6 and above</h3>
WordPress 4.6 introduced <a href="https://make.wordpress.org/core/2016/07/06/resource-hints-in-4-6/" rel="nofollow ugc">native support for resource hints</a>. 
By default, this plugin defers to WordPress 4.6 and theme/plugin developers to responsibly prefetch the right assets. Sites running 
on older versions of WordPress will continue to get the previous behavior where all JavaScript and stylesheets had resource hints 
printed for them.
I’ve added a filter To restore the old behavior (hint everything) on WordPress 4.6 and above. To use it, add this line to 
your theme’s functions.php file or a custom plugin:
<pre><code>`add_filter('http2_render_resource_hints', '__return_true');```
</code></pre>

HTTP/2 Server Push

This plugin helped speed up my website by 33%!

Works as advertised

This plugin does just what it says it'll do, HTTP/2 pushes everything!  

That generally will speed things up unless you have a ridiculous number of assets.  

While it now respects resource hinting for themes and plugins that provide that info, I do wish it had a UI for older themes/plugins to control what assets were going to be pushed instead of pushing them all. This plugin is so great without that though it still gets 5 stars

Speeds things up

Works perfectly in conjunction with Cloudflare to deliver excellent performance

Works perfectly

Enables HTTP/2 server push for local JavaScript and CSS resources.

Nico Martin

This plugin adds several performance improvements to your WordPress site. In contrst to other performance Plugins, this one sets focus on HTTP\2 Standards (like Server Push and SPDY).
<h4>minify assets</h4>
This plugin minifies all CSS and JS Files and caches them. It will not merge them into on file. This way you are still able to use conditional assets and if you are using HTTP/2, which I highly recommend, it’s not necessary to do so.
<h4>Optimizes JS Delivery</h4>
It moves all scripts to the footer and adds a <code>defer</code> attribute. This makes sure the scripts won’t block the page render process but will still be executed in the right order. 
In some cases, this could break inline JavaScript
<h4>Optimizes CSS Delivery</h4>
All CSS Files will be removed from the head and loaded asynchronously. This makes sure your CSS Files won’t delay the page rendering. To reduce the flash of unstyled content (FOUT) I recommend adding a Critical CSS.
conditonal Critical CSS
By default this plugin provides a textarea where you can put your critical CSS. 
Read more about <a href="https://github.com/nico-martin/Advanced-WPPerformance#conditonal-critical-css" rel="nofollow ugc">Conditional critical CSS</a>
Critical CSS API
We implemented an awesome new feature! 
Read more about the <a href="https://github.com/nico-martin/Advanced-WPPerformance#critical-css-api" rel="nofollow ugc">Critical CSS API</a>.
<h4>HTTP/2 Server Push</h4>
Server push is a HTTP/2 feature that allows you to send site assets to the user before they’ve even asked for them. 
There are two ways to achieve this. Both have their pros and cons. So this plugin supports both, the decision is up to you.
PHP
While WordPress builds your site, this plugin gets all enqueued scripts and styles and adds them as a link attribute to the response headers. That way you can be certain only files are being pushed, that are actually needed.
But: Since they are set while the server builds your site, this won’t work if you’re using a server caching (which I highly recommend).
.htaccess
The second option puts all files to push inside you .htaccess. This way they are being pushed also if you’re using server caching.
But: If your assets change (new versions / depreciated scripts), don’t forget to update the .htaccess. This can be done with one click while saving the settings.
<h3>Contribute</h3>
A development version of this plugin is hosted on github. If you have some ideas for improvements, feel free to dive into the code: 
<a href="https://github.com/nico-martin/Advanced-WPPerformance" rel="nofollow ugc">https://github.com/nico-martin/Advanced-WPPerformance</a>

Advanced WPPerformance

This plugin adds several performance improvements to your WordPress site. In contrst to other performance Plugins, this one sets focus on HTTP\2 Stand …

HTTP/2 Server Push vs Advanced WPPerformance