3 ms·
May start here: https://github.com/search?l=PHP&o=desc&q=php&s=stars&type=Repositories&utf8=%E2%9C%93 https://github.com/search?l=PHP&o=desc&q=php&s=stars&type=
by leftnode 12y ago
May start here: https://github.com/search?l=PHP&o=desc&q=php&s=stars&type=Repositories&utf8=%E2%9C%93 https://github.com/search?l=PHP&o=desc&q=php&s=stars&type=Re... and see what you find.
Particularly, the newer PHP frameworks, Guzzle, Composer, and PHPUnit are good to look at.