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

Fahad Alduraibi

Do you write posts in different languages that have different directions? 
This plugin enables a feature in the post editor which allow writing texts in Left-to-Right and Right-to-Left directions in the same post (or page) so you can write in English (and any other LTR language) and also RTL languages like Arabic, Persian and Hebrew.
Simply look for the new buttons added to the post editor after installing the plugin. (See the screenshots for better understanding)
اضافة زرارين لشريط التحرير لتمكين تحويل النص للقراءة من اليمين لليسار مثل اللغة العربية والفارسية والعبرية
<a href="http://www.fadvisor.net/blog/2008/10/wp-rtl/" rel="nofollow ugc">More details</a>
<ul>
<li>Note: This plugin will not change the direction of the post title, since that is controlled by the theme.</li>
</ul>

WP-RTL

Adds two buttons to the TinyMCE editor to enable writing text in Left to Right (LTR) and Right to Left (RTL) directions.

MarkdownBar vs WP-RTL