You can also look up for these other topics:
Framework
Coding Standards
Boilerplate
CMS
Tool
Security
Hacktoberfest
Trigger and listen to events within a PHP application
laminasComplete PHP-based Login/Registration system, Profile system, Chat room, Forum system and Blog/Polls/Event Management System.
msaad1999Event Espresso 4 Core for WordPress: Build an Event Ticketing Website Today!
eventespressoRun your own Events business with Eventmie. Use it as an event ticket selling website or event management platform on your own domain.
classiebit