A new site has started up that's trying to provide a listing of the "highest quality packages" out there for PHP based on PHP-FIG standards and good practices - the League of Extraordinary Packages.
The League of Extraordinary Packages has one driving mission, to track down and develop PHP packages of the highest quality possible, using modern tools, standards and practices to distribute, test and strengthen the code.
Members of The League follow the standards put forward by the PHP-FIG, follow the best practices detailed by PHP The Right Way and distribute all code through Composer.
So far there's a few on the list, but it promises to grow quickly. Libraries already included are things like Geotools, oauth2-client and statsd.