Alex Kozack

After loading the page, the plugin starts to follow the user’s screen. And as soon as a link appears on the screen within your site – the browser executes the request and downloads it. Now that the user clicks on the link, the browser will instantly display a new cache page. Thus, User Experience will indicate that your site is loading instantly.
<h3>How it work</h3>
The plugin uses the built-in browser features to predict user behavior for preloading the tourniquet. See <a href="https://en.wikipedia.org/wiki/Link_prefetching" title="Link prefetching" rel="nofollow ugc">this</a>
<h3>API</h3>
The plugin also registers a global feature that you can use to preload any URL:
<pre><code>window.prefetch('https://example.com/custom/page')
</code></pre>

Prefetch visible links

Preloads the page before the visitor clicks on the link.

Kevin Batdorf

Works out of the box. After activating, this plugin will pre-fetch the next web page just before your user clicks, thus giving the experience of an instant page load.
Better UX. Perfect for slower and shared web hosting plans.
This plugin is a wrapper for instant.page with some additional options and designed to be ready-to-go out of the box. No configuration needed.
More from <a href="https://instant.page/" rel="nofollow ugc">https://instant.page/</a> –
instant.page uses just-in-time preloading — it preloads a page right before a user clicks on it.
Before a user clicks on a link, they hover their mouse over that link. When a user has hovered for 65 ms there is one chance out of two that they will click on that link, so instant.page starts preloading at this moment, leaving on average over 300 ms for the page to preload.
Easy on your server and your user’s data plan
Pages are preloaded only when there’s a good chance that a user is going to visit them, and it preloads only the HTML of that page, being respectful of your users’ and servers’ bandwidth and CPU. It’s 1 kB and loads after everything else. And it’s free and open source (MIT license).
Some Technical Info: https://instant.page/tech

WP Instant Links

Have your site’s pages load instantly without having to do any custom coding.

Prefetch visible links vs WP Instant Links