Freemius

AuditySEO

AuditySEO Canonical Manager gives you complete, granular control over the canonical URL of every page on your WordPress site: posts, pages, custom post type entries, taxonomy terms, archive pages, and even the pagination pages WordPress generates automatically.
Missing or incorrect canonical tags are one of the most common technical SEO problems on WordPress sites. They let search engines index duplicate versions of the same content, split your ranking signals across multiple URLs, and waste crawl budget on pages that should never compete for the same keywords. AuditySEO Canonical Manager fixes this at the source, so every URL on your site points search engines to the page you actually want ranked.
<h4>Free features</h4>
<ul>
<li>Lists pages, posts, custom post types, terms and archives in a dedicated AuditySEO Canonicals admin screen.</li>
<li>Shows the default canonical URL that WordPress (or your SEO plugin) would output for each item.</li>
<li>Detects content pagination created with the <code></code> tag.</li>
<li>Detects pagination of the posts page (<code>page_for_posts</code>) based on the number of published posts and <code>posts_per_page</code>.</li>
<li>Detects pagination of taxonomy term and archive listings.</li>
<li>Lets you set a custom canonical URL per item and per pagination page.</li>
<li>Applies your overrides through the canonical filters of WordPress core, Rank Math and Yoast SEO.</li>
<li>Rewrites the <code><link rel="canonical"></code> tag in the final HTML output as a fallback for themes, caches and plugins that print a canonical outside of those filters.</li>
<li>Imports and exports canonical overrides via CSV, with a dry-run preview before bulk changes are applied.</li>
<li>Validates canonical URLs when you save them (HTTP status, redirects, noindex, external domain) without blocking the save, and flags the affected item with the reason until it is fixed.</li>
<li>Filters the editor by status, override state and pagination.</li>
</ul>
<h4>Pro features</h4>
Upgrade to AuditySEO Canonical Manager Pro to unlock:
<ul>
<li>History & restore – every change to a canonical override is recorded with the user and date, and can be rolled back with one click.</li>
<li>Automatic canonical fixes, applied site-wide:
<ul>
<li>Replace pagination canonicals that point to page 1 with each page’s own self-referencing URL.</li>
<li>Strip tracking parameters (utm_*, gclid, fbclid, msclkid, and more).</li>
<li>Strip display-variant parameters (print, amp, output, format, replytocom, and more).</li>
<li>Force the canonical to always match the requested URL exactly, including its query string.</li>
</ul>
</li>
</ul>
The free version is fully functional on its own and does not require the Pro upgrade to manage canonical overrides, detect pagination, validate URLs or import/export CSV files.

AuditySEO Canonical Manager

Full control over canonical URLs for posts, pages, CPTs, taxonomy terms, archives and paginated pages, with validation, history and auto-fixes.

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.

AuditySEO Canonical Manager vs Replytocom Controller