Scott Taylor

Similar to what we use on eMusic – this software is still experimental, but take a look!
Automagically concatenates JS and CSS files that are output in wp_head() and wp_footer() – stores / serves them from Memcached (if installed) or Database. In a load-balanced environment, the generation of flat files can be expensive and hard to distribute. Minify takes advantage of Memcached and Site Options / Transients to do the work once and share it among all servers in your cluster. File names are dynamically-generated to allow cache-busting of a CDN like Akamai that doesn’t always cache-bust by query string.
New .htaccess rule! 
 RewriteRule ^([_0-9a-zA-Z-]+)?/?wp-content/cache/minify-(.+)-(.*).(css|js)$ /wp-content/plugins/minify/make.php?hash=$2&type=$4&incr=$3&site=$1 [L]

Minify

Automagically concatenates JS and CSS files that are output in wp_head() and wp_footer()

Kuba Mikita

Just install it and get URL’s working – no coniguration is required.
This plugins fix errors with:
<ul>
<li>CSS</li>
<li>JS</li>
<li>Fonts (also with Google fonts)</li>
</ul>
Also with this plugin you can get rid of “Asset from origin ‘XXX’ has been blocked from loading by Cross-Origin Resource Sharing policy: No ‘Access-Control-Allow-Origin’ header is present on the requested resource. Origin ‘XXX’ is therefore not allowed access.”

Polylang assets URLs fix

This plugin properly handles assets URLs when using different domains for each language

Minify vs Polylang assets URLs fix