Works perfectly with WordPress 5.1 and supports backreferences

I am using this plugin to search and replace the output of shortcodes in WordPress 5.1. It’s not mentioned in the documentation but this plugin supports backreferences!

The actual code to search and replace looks like this:

$buffer = preg_replace( $find, $far_settings['farreplace'][$key], $buffer );

So you can use PHP style regular expressions and backreferences ($1, $2, etc).