Jackson Whelan

Allows you to paste iframe codes in the visual editor, just enclose within the [iframe][/iframe] shortcode.

iframe Shortcode

Paste iframe embed codes into the visual editor.

Stefano Lissa

Include Me helps to include in posts or pages external files usually to be shared 
between different posts or pages or that contains PHP or other code that can be 
compromised by the visual editor.
The use is immediate: the shortcode [includeme] is all that you need (see the documentation 
on <a href="https://www.satollo.net/plugins/include-me" rel="nofollow ugc">Include Me official page</a>).
The best way to use it is to include functionalities 
written in external PHP that will be rendered in post body or to include pieces of 
javascript that will be hard to add with WordPress editor.
Inclusions can be rendered with IFRAME if needed to create boxes that display 
external web pages.
This plugin is made of few line of code, ultralite!
Other plugins by Stefano Lissa:
<ul>
<li><a href="https://www.satollo.net/plugins/hyper-cache" rel="nofollow ugc">Hyper Cache</a></li>
<li><a href="https://www.thenewsletterplugin.com" rel="nofollow ugc">Newsletter</a></li>
<li><a href="https://www.satollo.net/plugins/header-footer" rel="nofollow ugc">Header and Footer</a></li>
<li><a href="https://www.satollo.net/plugins/thumbnails" rel="nofollow ugc">Thumbnails</a></li>
</ul>
<h4>Translation</h4>
You can contribute to translate this plugin in your language on <a href="https://translate.wordpress.org" rel="nofollow ugc">WordPress Translate</a>

Include Me

Include Me helps to include any external file (textual, HTML or PHP) in posts or pages.

iframe Shortcode vs Include Me