Fumiki Takahashi

TAROSKY INC.

Add iframe block for block editor. 
WordPress editor sometimes cleans up <code>iframe</code> tag if the user is a contributor(single site) or an editor(multi site) who has no capability <a href="https://wordpress.org/support/article/roles-and-capabilities/#unfiltered_html" rel="ugc">unfiltered_html</a>.
This plugin simply add 1 custom block iframe block. That’s all and no config.
<h4>Features</h4>
<ul>
<li><code>iframe</code> tag not escaped.</li>
<li>Responsive supported.</li>
<li>Keep aspect ratio. Default is <code>16:9</code>.</li>
<li>Keep <code>iframe</code> unescaped even in multisite. If you have multiple writers in your site, this might help without any roles-and-capabilities knowledge.</li>
<li>Align full and align wide supported.</li>
</ul>

Taro iframe Block

Add iframe block for your editor. Responsive and keeping aspect ratio.

John Godley

PageView is a plugin that will display another web page inside the current post. This is achieved with the use of an 
iframe – an HTML tag that allows a webpage to be displayed inline with the current page.
To use:
<pre><code>[pageview url="http://urbangiraffe.com"]
</code></pre>
Optional arguments:
title = A title to show under the iframe 
desc = A description to show under the iframe 
width = Width of iframe, in px or % 
height = Height of iframe, in px or %
<h3>Documentation</h3>
Full documentation can be found on the <a href="http://urbangiraffe.com/plugins/pageview/" rel="nofollow ugc">Pageview</a> page.

PageView

Insert an iframe and display an external website directly in a post using just a shortcode.

Taro iframe Block vs PageView