crimson090

Adds buttons to the Text (HTML) edit which generate Markdown syntax. These buttons serve as a great introduction to 
users who are new to Markdown, as well as shortcuts for more experienced users. The buttons include:
<ul>
<li>Bold</li>
<li>Italic</li>
<li>Blockquote</li>
<li>Link</li>
<li>Code</li>
<li>Table</li>
<li>Headers</li>
<li>Help (links to external Github Markdown guide)</li>
</ul>
This plugin does not modify the Visual editor, as that editor is not ideal for writing Markdown in. It’s recommended you disable 
the Visual editor entirely to enforce using Markdown.
Note that this plugin does not render Markdown. You should use a plugin (such as Jetpack Markdown) to render markdown in your theme.

MarkdownBar

Adds a toolbar of buttons to the Text (HTML) edit which generate Markdown syntax

feedmeastraycat

Note: This plugin still works but it doesn’t really contain any major features that the native Text widget is missing. The plugin is no longer in active developement.
This plugin adds a rich text widget where the content is edited using the standard WordPress visual editor which most users already are familiar with. 
It uses the WP core function wp_editor() without adding a custom post type post for each widget making the widget quicker and simpler to edit.
Feel free to help with developement or issue reporting on <a href="https://github.com/feedmeastraycat/wp-editor-widget" rel="nofollow ugc">Github</a>!
<h4>Languages</h4>
<ul>
<li>English</li>
<li>Swedish</li>
<li>German</li>
<li>Danish</li>
<li><a href="https://translate.wordpress.org/projects/wp-plugins/wp-editor-widget" rel="nofollow ugc">More translations</a></li>
</ul>

WP Editor Widget

I used it to add client instructions to an admin page. This makes adding screenshots and video quite easy.



Works Perfectly

WP Editor Widget adds a rich text widget where the content is edited using the standard WordPress visual editor.

MarkdownBar vs WP Editor Widget