WP Plover

Unlike popular documentation plugins that have opinionated layouts and styles. Plover Doc is based on Gutenberg Blocks and you can create any layout and style to match your brand, No fees or touch the code. Also, it’s kept as simple as possible and won’t slow down your site.

Plover Doc – Block based documentation, knowledge base and Wiki.

Plover Doc is a documentation, knowledge base and Wiki plugin based on Gutenberg Blocks and you can create any layout and style to match your brand.

WP HelpKit

Create, Organize and Publish help content.
A simple tool for creating Knowledge Base and Documentation sites 
for your software products.
HelpKit for documentation sites 
is what WooCommerce is for eCommerce sites.
<h3>What can I do with HelpKit?</h3>
<ul>
<li>Help Center / Support Sites</li>
<li>Knowledge Base</li>
<li>Documentation</li>
<li>User Manuals</li>
<li>Wiki</li>
<li>FAQs</li>
</ul>

WPHelpKit

We've just started using it to document our WooCommerce themes and it seems to be exactly what we were looking for.

Exactly what we need

Create a fully featured Help Center site (Knowledge Base, Documentation, Wiki, FAQs) with WordPress.

Plover Doc – Block based documentation, knowledge base and Wiki. vs WPHelpKit