superann

This plugin filters the sitewide comments feed as well as individual post comment feeds.
Upon first-time installation and activation, all trackbacks will be removed from the default WordPress comments feeds. 
You can override this behavior on the options page and also use the comments or trackbacks only feeds described below.
URL for comments only feeds: add the variable “comments” to your feed query string.
<ul>
<li>http://mysite.com/comments/feed/?comments</li>
<li>http://mysite.com/?feed=rss2&withcomments=1&comments</li>
</ul>
URL for trackbacks only feeds: add the variable “trackbacks” to your feed query string.
<ul>
<li>http://mysite.com/comments/feed/?trackbacks</li>
<li>http://mysite.com/?feed=rss2&withcomments=1&trackbacks</li>
</ul>

Separate Feed Comments and Trackbacks

Remove trackbacks from your sitewide and individual post comment feeds, and/or have alternate feeds for comments or trackbacks only.

Ptah Dunbar

The Comments Loop widget was written to allows users with no coding knowledge to customize their comments loop and comments form, all without editing their comments.php file.
Comments Loop is a complete widigitzation of the comments.php file, with over 30 settings to customize from reply links to what gets displayed when comments are closed. When you activate Comments Loop, you’ll have two new available widgets, Comments Loop and Comments Form. Simply drag and drop them in a sidebar that’s active in a singular template (e.g. single.php, page.php, or attachment.php).
View the <a href="https://wordpress.org/extend/plugins/comments-loop/faq/" rel="ugc">FAQ</a> section for more info on how to use Comments Loop.

Comments Loop

A WordPress widget that gives you unprecendeted control over displaying your comments loop and comment form.

Separate Feed Comments and Trackbacks vs Comments Loop