How to embed or attach a list of contacts in an email?
Sounds like you're looking for CiviCRM Views Token.

This is a Drupal module which allows you to place a token in your CiviMail that will be replaced with the output of a Drupal View.

To use it:


Install and enable CiviCRM Views Token
Build your view of contacts in Drupal - keep the output simple, eg a table or an unformatted list.
In your CiviMail edit screen, look for "Configured Drupal View" in the token selector.
Place the desired view in your email, eg {civicrm_views_tokens.viewcontactlist}