Donncha O Caoimh (a11n)

This plugin allows a blog administrator to test a new theme while showing the old theme to regular visitors.

Theme Tester

Test a theme on your blog without showing your visitors

codersantosh

AcmeIT

gutentor

Templateberg

<a href="https://www.templateberg.com" rel="nofollow ugc">Templateberg</a> is the finest collection of <a href="https://templateberg.com/gutenberg-templates/" rel="nofollow ugc">WordPress Gutenberg Templates</a> and <a href="https://templateberg.com/wordpress-themes-template-kits/" rel="nofollow ugc">WordPress Theme Template Kits</a>. Templateberg includes a tremendous listing of templates created in modern and fascinating styles from multipurpose to any niche which will accompany you with more excitement for designing your web pages.
<h3>Gutenberg Templates Some Terminology</h3>
<ul>
<li>Template Kits: Template kits are a collection of different page templates like home, about, contact, team etc to create a complete website.</li>
<li>Templates: Templates are single-page designs. It can be a different landing page design.</li>
<li>Blocks: Blocks are a single section of a template. Probably the most modern way to create a template is by combing the block design the possibility to create a unique template is infinite.</li>
</ul>
<h3>WordPress Themes Template Kits</h3>
<a href="https://templateberg.com/wordpress-themes-template-kits/" rel="nofollow ugc">WordPress Theme Template Kits</a> are pre-designed templates, demos or mockups for a specific theme that you can import with a click to have a project quickly and beautiful.
<h3>Features</h3>
Captivating Free Templates: 
The amazing templates designed are just one click away from loading into your website. Sign up now and have great options for the template or block design.
Preview, Search and Filter Templates: 
Before importing templates you can preview the templates. Search and Filter help to quickly find what you are looking for.
Harmonious Integration with Gutenberg Block editor: 
Its brilliant integration with Gutenberg Block editor makes it more interesting and users friendly.
Includes 100+ Gutenberg Free Templates: 
The site consists of 100+ pre-built Gutenberg templates or blocks ready for our cherished clients.
WooCommerce Templates: 
Templateberg includes stunning templates for WooCommerce design. Creating your online store will be easier now.
Easy Digital Downloads Templates: 
Templateberg also includes templates for Easy Digital Downloads, perfect to create or redesign your digital store.
Awesome Support 
Our team highly prioritizes and provides consistent support service to its users.
<h3>Enjoying Templateberg?</h3>
<ul>
<li>Like us on our <a href="https://www.facebook.com/templateberg" rel="nofollow ugc">Facebook Page</a>.</li>
<li>Follow us in <a href="https://twitter.com/templateberg" rel="nofollow ugc">Twitter @templateberg</a>.</li>
<li>Learn from our tutorials on <a href="https://www.youtube.com/watch?v=noppoc1zLIk&list=PLDLpZS3H6SMnpUnrU84LwFs9AAzTYcbmA" rel="nofollow ugc">YouTube Videos</a>.</li>
<li>Or rate us on <a href="https://wordpress.org/support/plugin/templateberg/reviews/?filter=5/#new-post" rel="ugc">WordPress</a> 🙂</li>
</ul>

Templateberg – Gutenberg Templates, WordPress Themes Template Kits & WordPress Templates

I am seeing this type of plugin probably the first time. Nicely done and nice concept. Good luck!

Nice Concept

Templateberg offers Gutenberg templates & WordPress theme kits. Import pre-designed layouts & build beautiful sites fast.

Theme Tester vs Templateberg – Gutenberg Templates, WordPress Themes Template Kits & WordPress Templates