The MERN stack (MongoDB, Express.js, React, and Node.js) is a popular stack for building web applications using JavaScript, and there isn't a direct equivalent in PHP. However, there are several PHP-based stacks that are commonly used for building web applications.
Here are a few examples:
LAMP stack (Linux, Apache, MySQL and PHP) is one of the most popular stacks for building web applications using PHP. It is commonly used to build websites and web applications.
MEAN stack (MongoDB, Express.js, AngularJS and Node.js) is another popular stack for building web applications. The MEAN stack is similar to the MERN stack, but it used AngularJS which requires a database.
Yii (PHP) + AngularJS, Yii is a high-performance PHP framework that can be used to build web applications quickly and easily. It can be used with AngularJS to create a full-stack web application.
Laravel (PHP) + Vue.js, Laravel is a popular PHP framework, and Vue.js is a JavaScript framework for building user interfaces. Together, they can be used to build web applications with a rich user interface.
Symfony (PHP) + React, Symfony is another popular PHP framework and React can be used to build the front-end framework or library you prefer.
It's also worth noting that, the stack you choose depends on your personal preference, the complexity of your project and the specific requirements of your applications.