designupjp

This plugin includes custom blocks that empower you to build layouts directly within the WordPress editor functionality. You can use the blocks to create responsive sites and original layout patterns.
Source Code / Development
The source code for OrigamiUI is publicly available on GitHub. You are welcome to review the code, report issues.
<ul>
<li>GitHub Repository: <a href="https://github.com/takeshi-du/origamiui" rel="nofollow ugc">origamiui</a></li>
</ul>

OrigamiUI

Provides custom blocks for building layouts within the WordPress editor.

Jonathan Desrosiers

Linchpin

Aaron Ware

<blockquote>
Similar functionality has been developed for the <a href="https://developer.wordpress.org/themes/advanced-topics/customizer-api/" title="Theme Customizer API" rel="nofollow ugc">Theme Customizer API</a> and was <a href="https://make.wordpress.org/core/2016/01/28/previewing-site-responsiveness-in-the-customizer/" rel="nofollow ugc">merged into WordPress core as of version 4.5</a>. This plugin will automatically deactivate when you install WordPress 4.5.
</blockquote>
When viewing the front end of the site, a “Responsive” button is added to the WordPress Toolbar. Clicking that will toggle an overlay with your website presented in various sizes for easy responsive design testing.
This can be useful both during theme development, and when writing content to verify it will be presented properly.
This plugin is a heavily modified version of <a href="http://mattkersley.com/" title="Matt Kersley's" rel="nofollow ugc">Matt Kersley’s</a> <a href="http://github.com/mattkersley/Responsive-Design-Testing" title="Responsive Design Testing" rel="nofollow ugc">Responsive Design Testing</a>.

Responsive Page Tester

Gives users with content creating permissions the ability to preview their site in a responsive testbed.

OrigamiUI vs Responsive Page Tester