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 …

ClaytonL

Hate duplicate content? Hate wasting server resources?
Replytocom Controller gives you the option to remove “?replytocom” from comment urls and optionally redirect visitors & bots who try to use it anyway to a destination of your choice.
For those concerned about duplicate content for SEO purposes, the benefits should be obvious.
If you want to speed up your WordPress server, the redirection will let you stop wasting resources serving up the same page over and over again to a crawler bot. Even worse, pages with a question mark in the url aren’t typically cached by caching plugins like WP Super Cache. That means that those bot crawls are eating up way more resources then a normal url would. Now you can send them to a cached copy of that page, a less resource intensive page, or any other url.
Of course, the cost of all this is that visitors can’t have JavaScript turned off if they want to leave replies in threaded comments.
Borrows code from: 
* https://wordpress.org/extend/plugins/all-in-one-seo-pack/ 
* https://wordpress.org/extend/plugins/replytocom-redirector/

Replytocom Controller

Replytocom Controller lets remove "?replytocom" from comment reply urls and redirect bots who try to use it anyway.

reCAPTCHA Lite vs Replytocom Controller