Display all page which have not a certain template

Question

You can add an OR relation to the meta query and also get pages with no _wp_page_template meta key:

$args = array(
    'post_type' => 'page',
    'posts_per_page' => -1,
    'order'  => 'ASC',
    'orderby' => 'title',
    'meta_query' => array(
        'relation' => 'OR',
        array(
            'key' => '_wp_page_template',
            'value' => 'template-rubrique.php',
            'compare' => '!=',
        ),
        array(
            'key' => '_wp_page_template',
            'compare' => 'NOT EXISTS',
        )

    )
);