Derrick Hammer

This plugin will combine all inline and external CSS in the order found on the page and save it to WP-Rocket’s cache folder as a new file. Files with media attributes are wrapped in <code>@media</code> selectors during processing. Async is powered by <a href="https://github.com/filamentgroup/loadCSS" rel="nofollow ugc">https://github.com/filamentgroup/loadCSS</a>.
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Filters <code>rocket_async_css_process_style</code> and <code>rocket_async_css_process_file</code> can be used to selectively exclude any inline CSS or external CSS from minify and async loading.
Examples are:
<pre><code>function exclude_css($skip, $css){
 if ( false !== strpos( $css, 'something' ) ) {
 return false;
 }

 return $skip;
}
add_filter('rocket_async_css_process_style','exclude_css', 10, 2);
</code></pre>
and
<pre><code>function exclude_file($skip, $url){
 if ( 'some url' == $url ) {
 return false;
 }

 return $skip;
}
add_filter('rocket_async_css_process_style','exclude_file', 10, 2);
</code></pre>

WP Rocket ASYNC CSS

WordPress plugin to combine all inline, external, and remote CSS and load async. Depends on WP-Rocket

This is NOT an official addon to WP-Rocket!

PI Web Solution

<ul>
<li>
Push / Pre-load all JS files in site with one simple option
</li>
<li>
Push / Pre-load all the CSS files in your website
</li>
<li>
Push / Pre-load other resources throughout the site or based on the page types
</li>
<li>
Load CSS Asynchronous or Remove any CSS file throughout the site, or there is a conditional selector that you can apply
</li>
<li>
Async / Defer / Remove any JS file throughout the site or based on the WordPress page type
</li>
<li>
You can create mobile device specific rule to push, pre-load, remove, async js or css, this works based on the device user agent detection
</li>
<li>
You can create desktop device specific rule to push, pre-load, remove, async js or css, this works based on the device user agent detection
</li>
<li>
Conditionally remove JS and CSS from various WooCommerce pages like checkout page, cart page, product page, product category page
</li>
<li>
You can push pre-load resource specific on some pages by their ID
</li>
<li>
Remove CSS, JS specific to page or post by their ID
</li>
<li>
Organize rules in group for easy management of the rules
</li>
<li>
Remove CSS, JS on all pages leaving only on the page you specified
</li>
<li>
optimize WooCommerce speed
</li>
<li>
optimize WordPress website speed
</li>
</ul>
<iframe loading="lazy" title="Http2 push preload plugin working for WordPress" width="750" height="422" src="https://www.youtube.com/embed/GHGclxgbSqI?feature=oembed" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
<blockquote>
Mobile and Desktop detection works based on the wp_is_mobile() function of the WordPress that detect device based on the user agent data send in the request
</blockquote>
Apart from this it also offer ability to remove Css and JS file from specific pages based in the selected page tag conditions
Eg: if css path is https://s.w.org/style/wp4.css
then you can match it with wp4.css or style/wp4.css or s.w.org/style/wp4.css
you use 2nd method (style/wp4.css) for more precise selection (this avoid error when there are 2 style with same file name)

Page Speed Optimizer: HTTP/2 Push, Async JavaScript, and Defer CSS

My websites are entirely in AMP, but this plugin injects non-AMP scripts on evey page. It doesn't even try to inject scripts only in non-AMP. So, kinda useless for me. I hope to give it another try in the future.

Not compatible with AMP

It is one of my mandatory plugins, I always use it. :)

Simple, handy and must-have :)

HTTP2 Server push, Async JavaScript, Defer Render Blocking CSS, with fine rule set to control js and css on different page types,

WP Rocket ASYNC CSS vs Page Speed Optimizer: HTTP/2 Push, Async JavaScript, and Defer CSS