wpblockbuddy

With the Controlled Content Block you can create a Content section where you have control over which blocks are allowed. Use this block if you have a section where you only want paragraphs. The block also features a filter to control who can change which type of blocks are available. The possible allowed core blocks are paragraphs, lists, headings, and images. If you would like to add or remove blocks from these choices there is a filter for that too.
The block also features a filter to remove the meta box for selecting allowed blocks for certain users.
<a href="https://wpblockbuddy.com/blocks/controlled-content-block/" rel="nofollow ugc">View Information on filters and additional documentation.</a>

Controlled Content Block

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.

Controlled Content Block vs Responsive Page Tester