bbPress.org

Use the hook <?php do_action( 'bbp_template_notices' ); ?> or even <?php do_action( 'bbp_theme_before_topic_form_notices' ); ?>

And here is an example for a custom notice. You can of course add a list, but you would need to style it with some CSS.

function rkk_add_notice_before_topic_form() {
    ?>
        <div class="bbp-template-notice important">
          <p>
             <strong>IMPORTANT!:</strong> Make sure to read our site's <a href="http://yoursite.com/discussion-policy"> discussion policy</a> before you post.
          </p>
        </div>
    <?php
 }
 add_action( 'bbp_theme_before_topic_form_notices', 'rkk_add_notice_before_topic_form' );