Require WordPress mu-plugins in vanilla wp projects.

autoloader.php

<?php
  /*
    Plugin Name:  B&S Autoloader
    Plugin URI:   https://github.com/borgenfalkskott
    Description:  Mu-plugin autoloader for vanilla Wp.
    Version:      1.1.0
    Author:       Borgenfalk & Skott
    Author URI:   https://borgenfalk.se
    License:      MIT
  */

  defined( 'ABSPATH' ) or die( 'No script kiddies please!' );

  require_once __DIR__ . '/bs-wp-reset/bs-wp-reset.php';
  require_once __DIR__ . '/bs-wp-meta/bs-wp-meta.php';
  require_once __DIR__ . '/bs-wp-no-jquery/bs-wp-no-jquery.php';
?>

NOTE: You only need this autoloader if your plugin lives in a sub folder e.g. /plugin-name/plugin-name.php

Place the autoloader.php in /wp-content/mu-plugins/.
WordPress looks automatically for plugin files in the mu-plugins folder.