How to create notification on frontend using heartbeat api for multiple custom post types

I think you can achieve this by:

1.determine the custom post types by using get_post_types() fx

It returns a list of post names or objects on basis of parameter you
pass

<?php
$args = array(
  'public'   => true,
  '_builtin' => false
); //pass parameter to array according to get all custom post types( parameter pass for demo only.modify it to get desire result)
$post_types=get_post_types($args,'names');

?>

2.add action to custom post type when publish

<?php
foreach($post_types as $post_type){
  add_action( 'publish_'.$post_type, 'ravs_notify_published_post' );
}
function ravs_notify_published_post( $post_id ) {
 $post = get_post( $post_id );
 // Here's the magic
 Wp_Heartbeat_Notify::notify( array(
    'title'     =>      'New Post by ' . $post->post_author,
    'content'   =>      'There\'s a new post publish, why don\'t you <a href="' .get_permalink($post_id). '">give it</a> a look?',
    'type'      =>      'info'
  ));
}
?>

Updated

Create a plugin to show realtime notifications WP-Realtime-Notify

Edit

Paste this code in functions.php.It’ll print array of name of custom post types.goto get_post_types and see all parameters.pass correct parameters which gives you required output( change $args ).if you get correct array of name of custom post types for required $args,change it with my $args in plugin.

<?php
add_action('the_content','ravs_customPostList');
function ravs_customPostList(){
$args = array(
  'public'   => true,
);
$post_types = get_post_types($args,'names'); //get names of post types
print_r($post_types);
}?>