zingming

Hide unwanted comments without deleting them. Edit the comment and wrap the offending text in [shush][/shush]. Example: [shush]FIRST!!![/shush] or [shush reason=”Boring”]FIRST!!![/shush]
Readers can choose to read the buried comment by clicking on the “Show” link.
(Bonus: You can also use this shortcode in your posts as a “Spoiler” hider.)

ShushThatNoise – Ignorant Comment Hider

Hide unwanted comments without deleting them. Readers can click on the "Show" link to read the buried comment.

Umbrovskis.com

List of spammers in <a href="https://wordpress.org/plugins/wp-referrer-spam-blacklist/faq/" rel="ugc">FAQ</a>.
No need for configuration! Plugin in background redirects referral spammer to blank page ( about:blank ). Redirect link can be altered via filter <code>wp_referralblock_redirect_uri</code>.
NO auto update, as we see that as possible as security hole. We do not wan’t Your site to get hacked.
Plugin is for sites that can’t edit their <code>.htaccess</code> or configure NGINX or Apache servers.
Via <a href="http://go.mediabox.lv/1LbSuKq" rel="nofollow ugc">my LinkedIN post</a>: Few months ago I started to collect referral spam pages in private file un bitbucket.org. Problem was that I did not know all spammers. Then, few weeks ago, I found that Matomo (Open source analytics) started their own “project”, and they did the same thing I did – collected referral spam sites to block them from Your website.
On my own server I do that at server level, but some of my clients have hosting, where You can not edit server settings. This week I came up with another solution – WordPress plugin “WP referrer spam blacklist”. I will update list every week from <a href="https://github.com/matomo-org/referrer-spam-blacklist" rel="nofollow ugc">Matomo’s community-contributed list of spammers</a>.
If You have WordPress site and no knowledge about or access to server settings, I made that for You!
From <a href="https://en.wikipedia.org/wiki/Referer_spam" rel="nofollow ugc">Wikipedia</a>:
<pre><code>Referrer spam (also known as log spam or referrer 
bombing) is a kind of spamdexing (spamming aimed 
at search engines). The technique involves making 
repeated web site requests using a fake referer URL 
to the site the spammer wishes to advertise. Sites that 
publish their access logs, including referer statistics, 
will then inadvertently link back to the spammer's site. 
These links will be indexed by search engines 
as they crawl the access logs. 

This benefits the spammer because the free link improves 
the spammer site's search engine ranking owing 
to link-counting algorithms that search engines use.
</code></pre>
Other plugins by author: <a href="https://wordpress.org/plugins/itempropwp/" rel="ugc">itemprop WP for SERP/SEO Rich snippets</a> – Add schema.org itemprop code to the (custom) post content for search engines and bots for better SERP results

WP referrer spam blacklist (fight 2040+ Referrer Spammers in (Google/Matomo) Analytics)

WordPress plugin to fight with 2040+ referrer spammers (like semalt, buttons-for-website and many more).

ShushThatNoise – Ignorant Comment Hider vs WP referrer spam blacklist (fight 2040+ Referrer Spammers in (Google/Matomo) Analytics)