The Doctrine Event Manager is a library that provides a simple event system.

The easiest way to get started with event sourcing in Laravel

Boost the performance of nearly any PHP app effortlessly with Workerman, enabling faster and asynchronous execution—all without modifying a single line of code in your framework or app. Additionally, leverage Workerman as a powerful Serverless solution for scalable, event-driven workloads. It's lightweight design and high efficiency

Asynchronous coroutines for PHP 7.

The Hoa\Event library

A Photobooth web interface for Linux and Windows.

A Minimalistic PHP Event Sourcing / CQRS Library experiment that probably still works.

Like IFTTT for Moodle: events to trigger external services. https://moodle.org/plugins/tool_trigger

WP Event Manager is a lightweight, scalable and full-featured event management plugin for adding event listing functionality to your WordPress site. The shortcode lists all the events, it can work with any theme and is really easy to setup and customise.

php bindings to the linux epoll API

MySQL/JSON integration with FullCalendar and event recurrence capabilities.

Fork of PHP Asterisk Manager Interface ( AMI ) supports synchronous command ( action )/ responses and asynchronous events using the pattern observer-listener. Supports commands with responses with multiple events. Very suitable for development of operator consoles and / or asterisk / channels / peers monitoring through SOA, etc

Eases handling remote events

PHP event manager. simple, fully functional event management dispatcher implementation. 简洁,功能完善的事件管理实现，支持快速的事件组注册，设置事件优先级，通配符事件的监听。

Symfony Event Queue Bundle

Event is a rich and efficient event library that supports synchronous dispatch events, asynchronous notification events, and network communication events.

The Events API Bundle for Akeneo PIM delivers catalog changes as events to a 3rd party systems.

StreamPulse is a Laravel package for event streaming with support for multiple drivers. It provides a simple, unified API for publishing and consuming events across different streaming platforms.

Article: Laravel PWA to implement Broadcasting

Eventmie Pro - PHP Script – Self-hosted multi-organization (multi-vendor) event management Laravel package (PHP script). Launch a dedicated platform for Event selling website on your own domain and streamline the event planning process through automation.