Display only authors

<?php
$user_query = new WP_User_Query( array( 'who' => 'authors' ) );
if ( ! empty( $user_query->results ) ) {
foreach ( $user_query->results as $user ) {
echo '<p>' . $user->display_name . '</p>';//display name of user with role Administrator
}
} else {
echo 'No users found.';
}
?>

OR

<?php
$args = array(
'meta_key'     => 'user_level',
'meta_value'   => '0',
'meta_compare' => '!=',
'blog_id'      => 0
);
$user_query = new WP_User_Query( $args );
if ( ! empty( $user_query->results ) ) {
foreach ( $user_query->results as $user ) {
echo '<p>' . $user->display_name . '</p>';//display name of user with role Administrator
}
} else {
echo 'No users found.';
}
?>