f13dev

Add Google reCaptcha to the comments section on blog posts. Requires Google reCaptcha v2 Checkbox API key.
Simple configuration via the admin settings page: 
* reCaptcha public key 
* reCaptcha private key 
* enable reCaptcha for (Everyone | Visitors | Nobody [disabled])
Additional hooks for programmers: 
$v = apply_filters(‘f13_recaptcha_add’); 
Will place a reCaptcha checkbox in the desired place.
$validate = apply_filters(‘f13_recaptcha_validate’); 
if (!empty($validate)) { 
 $v = $validate 
 // reCaptcha failed 
} else { 
 // reCaptcah passed 
}

F13 reCaptcha

Add Google reCaptcha to the comments section on blog posts. Additional hooks for adding reCaptcha to custom forms.

idengod

Protect your Contact Form 7 forms from spam and abuse. It can be used to protect multiple forms on the same page. Add an SVG image captcha and honeypot to your contact form 7 form. Our Advanced Contact Form 7 CAPTCHA is GDPR compliant and does not slow down your site with additional header requests like.
To use this plugin, you need to get an API key from google: 
https://www.google.com/recaptcha/admin 
This plugin implements ?I?m not a robot? checkbox on Contact Form 7 Forms.
While making a website, it is vital to make a website that is safe for both users and website owners. Everybody is aware of spammers flooding the internet. They misuse the website and keep posting spam comments. With our plugin, you can stop WordPress spam, comment spam, registration spam, fake subscriptions, brute force attacks.
An Effective Security Solution to Protect your Contact 7 Forms! Protect your website from spam, random unwanted users, and bots.
<h4>Stop spam now! Protect Your Site From Bots</h4>
Protecting your site against spam is very important and our powerful captcha for Contact 7 plugin offers safety and security in a number of ways.
Captcha for Contact 7 Forms is a simple and powerful plugin that provides easy-to-solve Captcha tests while still being hard on the bots. It protects your WordPress sites/blogs from spam entries by means of math logic and text images.
<h4>FEATURES</h4>
<ul>
<li>GDPR compliant</li>
<li>CAPTCHA refreshes on submitting to make it harder for automated spammers</li>
<li>Stronger security </li>
<li>Prevents SPAM</li>
<li>Google API</li>
</ul>

Advanced Captcha For Contact Form 7

Adds an advanced clean image captcha to Contact Form 7

F13 reCaptcha vs Advanced Captcha For Contact Form 7