ctomczyk

Spam Prevention for WP Contact Form 7 and WordPress Comments. 
This plugin adds a small code snippet to determine page scroll and add dynamically a unique token. 
It also supports the “Contact Form 7 Database Addon – CFDB7” and prevents contact form submissions from being saved if validation fails.
If the token doesn’t exists while submitting or call directly API then the incoming request will be rejected.
You can see how it works on <a href="https://www.sitelint.com/contact" rel="nofollow ugc">SiteLint</a> website.

Spam Prevention for Contact Form 7 and Comments

Spam Prevention for WP Contact Form 7 (manage multiple contact forms) and WordPress Comments.

web2dev

A simple comment captcha protection based on <a href="http://captcha.hsoub.com/" rel="nofollow ugc">Hsoub API</a> (support arabic & english).
<h3>About the plugin</h3>
This plugin use the great <a href="http://captcha.hsoub.com/" rel="nofollow ugc">Hsoub API</a>, and is a <a href="http://web2dev.me/" rel="nofollow ugc">web2dev</a> concept.

Spam Prevention for Contact Form 7 and Comments vs Hsoub CAPTCHA