WooThemes

Daan Kortenbach

Enables a preview mode for widgets. In preview mode, widgets are only visible for admins.

WP Widget Preview

Enables a preview mode for widgets. In preview mode, widgets are only visible for admins.

mraliende

The Plugin adds an link preview box to your post. 
The link preview box will be displayed like in Facebook! 🙂
This plugin can be used for free for maximal 10 URL Preview Boxes.
Perhaps you are familiar with Facebook. 
When you write a post in Facebook and you paste an URL into your text, 
Facebook detects that URL and adds automatically information about that URL under your post.
This plugin does it not automatically, you have to use the extra button in the visual editor (“URL BOX”). 
Or you just write [urlpreviewbox url=”\https://….”] into your text. 
This plugin loads information about that URL from https://guteurls.de/ server.
<ol>
<li>Title of that page</li>
<li>Description of that page</li>
<li>An URL of an image</li>
</ol>
And the plugin displays it below your post.
Facebook supports only one preview box per post. 
This plugin supports many preview boxes within one post, if you want.
Do you want to see it live on production servers?
Look here (copy and paste the URLs into your browser):
Example web pages, who use it:
https://alien.de/news/
https://www.ufo-und-alienforum.de/index.php/Thread/30805-Verlassene-Orte-in-Baden-Württemberg/
https://hypnose54321.de/frankfurt/_news.php
:
HOW TO USE IT VIDEO:
http://www.youtube.com/watch?v=4_wIzQbPg84 
<iframe loading="lazy" class="youtube-player" width="750" height="422" src="https://www.youtube.com/embed/4_wIzQbPg84?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent" allowfullscreen="true" style="border:0;" sandbox="allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox"></iframe>
<h3>Internationalization (i18n)</h3>
Currently we have the plugin configured so it can be easily translated and the following languages supported:
<ul>
<li>de_DE – German in Germany</li>
<li>en_US – English in the U.S.</li>
<li>zh_CN – China</li>
<li>es_ES – Spanish in Spain</li>
<li>ru_RU – Russian in the Russian Federation</li>
</ul>
If your language is not listed above, feel free to create a translation. Here are the basic steps:
<ol>
<li>Copy “gurlpb-en.pot” to “gurlpb-LANG_COUNTRY.pot” – fill in LANG and COUNTRY with whatever you use for WPLANG in wp-config.php</li>
<li>Grab a transalation editor. <a href="http://www.poedit.net/" rel="nofollow ugc">POedit</a> works for us</li>
<li>Translate each line</li>
</ol>

URL-Preview-Box

That was really needed, because the automatic URL detection failed sometimes at very different designed WordPress templates.
This is the WordPress plugin, what I exactly needed. 
I use it now and will use it in the next years for sure.

Now it is possible to add manually preview boxes

This plugin adds link preview box to your post. You just copied & pasted an URL into your posting. :-)

WP Widget Preview vs URL-Preview-Box