Remi Collet published an exhaustive list of PHP extensions that are already compatible with the upcoming PHP 8.0.

PHP extensions status with upcoming PHP 8.0

With PHP 8.0 entering stabilization phase, time to check the status of most commonly used PHP extensions (at least, the ones available in my repository). Here is the (mostly) exhaustive list.

PHP extensions status with upcoming PHP 8.0 - Remi's RPM repository - Blog