Malik Naik

The reCAPTCHA Lite protects your WordPress site from the bots, brute-force attacks, spam, and abuse. This plugin comes with the support of reCAPTCHA v3 and v2 Checkbox. The reCAPTCHA v3 allows users to navigate site without solving “I’m not a robot” challenges.
You can integrate the Google’s reCAPTCHA in the following forms:
<ul>
<li>Login Form</li>
<li>Registration Form</li>
<li>Lost Password Form</li>
<li>Reset Password Form</li>
<li>Comment Form</li>
<li>WooCommerce Forms</li>
<li>Buddy Press Signup Form</li>
</ul>
If you are using the Google reCAPTCHA v3 then the following actions list shows the action names that will be used to hit the <a href="https://developers.google.com/recaptcha/docs/verify#api_request" rel="nofollow ugc">Google’s reCAPTCHA API endpoint</a> during validation. For more information on actions checkout out the <a href="https://developers.google.com/recaptcha/docs/v3#actions" rel="nofollow ugc">official documentation</a>.
<ul>
<li>login_form</li>
<li>register_form</li>
<li>lost_password_form</li>
<li>reset_password_form</li>
<li>comment_form</li>
<li>woo_register_form</li>
<li>woo_order_checkout</li>
<li>woo_login_form</li>
<li>buddypress_signup</li>
</ul>

reCAPTCHA Lite

Integrate the Google's reCAPTCHA Google's reCAPTCHA v2 Checkbox or v3 into the forms and protect your site from bots, brute-force attacks, s …

sdesalas

This plugin allows WordPress to block over 95% of spam comments using a time-based hash.
This allows for a minimum sanity check and yet should remove almost all spam comments 
without the need to sign up to any third party APIs.
The plugin has been tested in real world conditions for around 12 months. It will not block 
real comments and it is pretty effective against spam, however it only uses a very simple 
algorithm and for that reason some spam comments may still make it through.

WP Simple SpamCheck

This plugin allows WordPress to block over 95% of spam comments using a time-based hash.

reCAPTCHA Lite vs WP Simple SpamCheck