Featured image column for default posts types

Hi,

You can use the custom admin columns to show the featured image in the listing posts/pages. Follow this documentation https://docs.metabox.io/extensions/mb-admin-columns/#custom-admin-columns

class My_Featured_Image_Columns extends \MBAC\Post {
    public function columns( $columns ) {
        $columns  = parent::columns( $columns );
        $position = 'before';
        $target   = 'title';
        $this->add( $columns, 'featured_image', 'Featured Image', $position, $target );
        // Add more if you want
        return $columns;
    }
    public function show( $column, $post_id ) {
        switch ( $column ) {
            case 'featured_image':
                the_post_thumbnail( [40, 40] ); //here
                break;
            // More columns
        }
    }
}

With the MB Builder, you can create a field with ID _thumbnail_id then show it as an admin column.