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

Coen Jacobs

Adds a custom post type that can be easily inserted at multiple spots, including widgets. Easy way to create WYSIWYG widgets.
This plugin is still alive. It has been tested to run on the most recent WordPress version and it still works fine. Future versions will bring more features and an updated code base.
Please use the <a href="https://wordpress.org/support/plugin/smart-wysiwyg-blocks-of-content" rel="ugc">support forums</a> to request support in case you have some kind of trouble. You can contribute to the plugin via the <a href="https://github.com/coenjacobs/smart-wysiwyg-blocks-of-content" rel="nofollow ugc">GitHub repository</a>. Pull requests or bug reports are very welcome there.

Smart WYSIWYG Blocks Of Content

Adds a custom post type that can be easily inserted at multiple spots, including widgets. Easy way to create WYSIWYG widgets.

MarkdownBar vs Smart WYSIWYG Blocks Of Content