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.

shawfactor

Server Push provides significant performance gains if used judiciously. However other WordPress plugins that handle server push can actually slow your site as they push files indiscrimentally.
Most push all files enqueued by wordpress to the broswer and use output buffering to achieve this.
However this plugin does it properly by only pushing the the assets that the browser requires for the initial user interaction. Namely the scripts and css in the head of the document.
Note : It requires a web server that supports HTTP/2.

LH HTTP/2 Server Push

Does HTTP/2 Server Push for JavaScript and CSS resources properly.

HTTP/2 Server Push vs LH HTTP/2 Server Push