Fivera

I will start with saying that the external links from our websites pass some of our own juice to the website that they link to. That is not a bad thing at all, i love my juice being passed to websites like WordPress.org or to the websites that have similar content like mine e.g. : websites of the plugin authors that i review and promote on fivera.net or a cool online tool that i use like Pingdom or codepen.io
But i certainly dont want my juice to go to exterminate rats with this great new poison website, only because the author has made a decent comment on one of my articles.
So I have created this simple yet effective plugin to keep the external links to the minimum. 
<a href="http://fivera.net/remove-links-comments-free-wordpress-plugin/" rel="nofollow ugc">Here</a>’s the page with more details about it.

Remove links from comments

This simple Plugin removes the website field in your comments and also hides all the hyperlinks from comment author user names.

Corey Salzano

This plugin removes all hyperlinks from comment author user names. Commenters can provide a home page (or any) URL along with their comment on a lot of themes. This plugin will strip all links from commenter names wherever they may appear throughout your site’s theme.

Disable Comment Author Links

Prevents comment author names from linking to external websites.

Remove links from comments vs Disable Comment Author Links