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

David Perez

closemarketing

Sacra Jáimez

Adds a button to your classic editor visual toolbar that when clicked strips all <code>div</code>, ‘table’, <code>span</code> tags from your post HTML code — those are usually junk tags. The stripping includes any tag attributes.

Cleanup HTML

Este plugin me ha sido ideal para traerme un contenido de un blog de blogger y limpiar el código. Es una pena que no lo sigan actualizando.

Es genial para importar contenido de otros CMS

Adds a button to your classic editor visual toolbar that when clicked strips all div, 'table', span tags from your post HTML code -- those a …

MarkdownBar vs Cleanup HTML