Samir Shah

This plugin will issue a HTTP <code>410</code> response to requests for articles that no longer exist on your blog. When you delete a post or page, it records the URL for that page and issues a <code>410</code> response when that URL is requested. You can also manually manage the list of obsolete URLs.
The <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.11" rel="nofollow ugc">HTTP Specification</a> defines the <code>410</code> response header for use when a resource has been permanently removed. It informs robots visiting your site that the requested content has gone, and that they should stop trying to access it.
If you come across any bugs or have suggestions, please use the plugin support forum. I can’t fix it if I don’t know it’s broken! Please check the <a href="https://wordpress.org/extend/plugins/wp-410/faq/" rel="ugc">FAQ</a> for common issues.

410 for WordPress

A plugin that sends HTTP 410 (Gone) responses to requests for articles that no longer exist on your blog.

edsteep

Force 410 HTTP Status on listed pages, or just articles/pages that no longer exist.
The <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.11" rel="nofollow ugc">HTTP Specification</a> defines the <code>410</code> response header for use when a resource has been permanently removed. It informs robots visiting your site that the requested content has gone, and that they should stop trying to access it.
If you come across any bugs or have suggestions, please use the plugin support forum.

410 Delete Pages SEO

Force 410 HTTP Status on listed pages, or just articles/pages that no longer exist.

410 for WordPress vs 410 Delete Pages SEO