Tekod lab.

Purpose of 404 page is to inform visitor that WordPress cannot resolve current URL, 
but leaves the visitor wondering why. 
Whether the page was deleted or simply the link was not typed correctly.
This plugin analyzes what is entered in the URL, compares it with all existing urls on the site, finds the closest ones and offers the visitor the 5 closest ones. 
Something like “did you mean…”.
<h3>Usage</h3>
The plugin supports both classic and block themes.
For classic themes, you need to add shortcode to the template of your 404 page:
 
For block themes, you will get a new Gutenberg block “404 page: similar links” that you simply insert into your template.
Finally, the plugin allows you to override template to completely customize resulting HTML, 
and a few filter hooks to modify its logic.
<h3>Contact</h3>
Please, send bug reports and feature requests to <a href="mailto:office@tekod.com" rel="nofollow ugc">office@tekod.com</a>

Suggest 404 links

Appends "did you mean" links to your "404" page.

david.kane

Supasearch enhances the default WordPress search.
The <a href="http://www.supadu.com/supasearch/" rel="nofollow ugc">Supasearch plugin</a> allows users to quickly and easily enhance the default search provided by WordPress. Just install and activate this plugin to have an immediately improved site search.
Features include:
<ul>
<li>Misspellings. If no results are found for a search term the plugin which check if the word is misspelt and provide results for the corrected word.</li>
<li>Did you mean?. If no results are found the plugin will offer a similar alternative for the user to search against.</li>
</ul>

Supasearch

Supasearch enhances the default WordPress search.

Suggest 404 links vs Supasearch