Shawn Hayes

This plugin allows you to add useful quicktag buttons to the Text (HTML) mode of the WordPress WYSIWYG editor. There is a settings page to choose from a list of quicktags you would like to use.
Currently on the list of options are: p, br, h1, h2, h3, h4, h5, h6, pb
This plugin was written by Shawn Hayes at <a href="http://sharewebdesign.com/" rel="nofollow ugc">Share Web Design</a> to make it easier to implement useful quicktag buttons. If you have any questions please feel free to visit our contact page at <a href="http://sharewebdesign.com/contact-us" rel="nofollow ugc">Contact Us</a> or post a question in the support area at <a href="https://wordpress.org/support/plugin/simple-quick-tags" rel="ugc">WordPress.org</a>.

Simple Quick Tags

Simple Quick Tags allows you to add useful quicktag buttons to the Text (HTML) mode of the WordPress WYSIWYG editor via a settings page.

Space X-Chimp

An easy to use, with intuitive interface, WordPress plugin that replaces the default Post & Page HTML/Text Editor with an enhanced editor by a <a href="https://codemirror.net/" rel="nofollow ugc">CodeMirror library</a>. The WordPress default Post & Page HTML/Text Editor is great for doing some custom changes to HTML markup of your post/page, although it is rather limited. This is where the “Syntax Highlighter for Post/Page HTML Editor” can help. With an enhanced HTML/Text editor you can see a code with syntax highlighting, and with line numbering, so you can easily read your HTML markup and detect any errors.
This plugin give you finer control over editor, it can be configured on the plugin settings page. You can chose from 36 different color themes for your editor. If you want more options, then let us know and we will be happy to add them.
This plugin is just plug and play, no tedious configurations or hacks, just install, enable and start using your new enhanced Post/Page HTML Editor.
Features
<ul>
<li>Lightweight and fast</li>
<li>Secure code with using clear coding standards</li>
<li>Intuitive interface with many settings</li>
<li>Cross browser compatible (work smooth in any modern browser)</li>
<li>Compatible with all WordPress themes</li>
<li>RTL compatible (right to left)</li>
<li>Translation ready</li>
</ul>
Key features include
<ul>
<li>Code syntax highlighting</li>
<li>Huge selection of color schemes (36 themes)</li>
<li>Line numbering</li>
<li>Line wrapping</li>
<li>Editor allow for Tab indentation</li>
<li>Live preview</li>
<li>And much, much more!</li>
</ul>
Supported languages:
<ul>
<li>Text</li>
<li>XML</li>
<li>HTML</li>
<li>CSS</li>
<li>JavaScript</li>
</ul>
Translation
This plugin is ready for translation and has already been translated into several languages. But If your language is not available then you can make one. It is also possible that not all existing translations are up-to-date or correct, so you are welcome to make corrections. Many of plugin users would be delighted if you share your translation with the community. Thanks for your contribution!
<ul>
<li>English (default)</li>
<li>Russian (translation by <a href="https://www.instagram.com/milava_kiseleva/" rel="nofollow ugc">Milena Kiseleva</a>)</li>
<li>German (translation by Michael)</li>
<li>Spanish (translation by Ramiro Garcés and Patricio Toledo)</li>
<li>Dutch (translation by Peter Leenders)</li>
<li>French (translation by Jean-Michel, Theophil Bethel and Hervé Bouzin)</li>
</ul>
If you want to help translate this plugin, please visit the <a href="https://translate.wordpress.org/projects/wp-plugins/syntax-highlighter-for-postpage-html-editor" rel="nofollow ugc">translation page</a>.
Minimum system requirements:
<ul>
<li><a href="https://wordpress.org">WordPress</a> version 4.9 or higher.</li>
<li><a href="https://secure.php.net" rel="nofollow ugc">PHP</a> version 5.6 or higher.</li>
<li><a href="https://www.mysql.com" rel="nofollow ugc">MySQL</a> version 5.0 or higher.</li>
</ul>
Recommended system requirements:
<ul>
<li><a href="https://wordpress.org">WordPress</a> version 5.0 or higher.</li>
<li><a href="https://secure.php.net" rel="nofollow ugc">PHP</a> version 7.0 or higher.</li>
<li><a href="https://www.mysql.com" rel="nofollow ugc">MySQL</a> version 5.6 or higher.</li>
</ul>
Contribution
Developing plugins is long and tedious work. If you benefit or enjoy this plugin please take the time to:
<ul>
<li><a href="https://www.spacexchimp.com/donate.html" rel="nofollow ugc">Donate</a> to support ongoing development. Your contribution would be greatly appreciated.</li>
<li><a href="https://wordpress.org/support/plugin/syntax-highlighter-for-postpage-html-editor/reviews/#new-post">Rate and Review</a> this plugin.</li>
<li><a href="https://www.spacexchimp.com/contact.html" rel="nofollow ugc">Share with us</a> or view the <a href="https://github.com/ArthurGareginyan/syntax-highlighter-for-postpage-html-editor" rel="nofollow ugc">GitHub Repo</a> if you have any ideas or suggestions to make this plugin better.</li>
</ul>
“Syntax Highlighter for Post/Page HTML Editor” is one of the own software projects of <a href="https://www.spacexchimp.com" rel="nofollow ugc">Space X-Chimp</a>.
License
This plugin is licensed under the <a href="http://www.gnu.org/licenses/gpl-3.0.html" rel="nofollow ugc">GNU General Public License, version 3 (GPLv3)</a> and is distributed free of charge. 
Commercial licensing (e.g. for projects that can’t use an open-source license) is available upon request.
Credits
<ul>
<li>The icon of this plugin is a copyrighted image created by the <a href="https://www.spacexchimp.com" rel="nofollow ugc">Space X-Chimp</a> team. (C) All rights reserved.</li>
<li>The banner of this plugin is a copyrighted image created by the <a href="https://www.spacexchimp.com" rel="nofollow ugc">Space X-Chimp</a> team. (C) All rights reserved.</li>
<li>Unless otherwise stated, all images are created by the <a href="https://www.spacexchimp.com" rel="nofollow ugc">Space X-Chimp</a> team and are copyrighted. (C) All rights reserved.</li>
<li><a href="https://codemirror.net/" rel="nofollow ugc">CodeMirror</a> is an open-source project shared under the <a href="https://codemirror.net/LICENSE" rel="nofollow ugc">MIT license</a>.</li>
<li><a href="http://getbootstrap.com" rel="nofollow ugc">Bootstrap</a> by Twitter, Inc. released under the <a href="https://github.com/twbs/bootstrap/blob/master/LICENSE" rel="nofollow ugc">MIT license</a>.</li>
<li><a href="https://github.com/vsn4ik/bootstrap-checkbox" rel="nofollow ugc">Bootstrap-checkbox</a> is a project of <a href="https://github.com/vsn4ik" rel="nofollow ugc">Vasily A.</a>, shared under the <a href="https://github.com/vsn4ik/bootstrap-checkbox/blob/master/LICENSE" rel="nofollow ugc">MIT license</a>.</li>
<li><a href="https://fontawesome.com" rel="nofollow ugc">Font Awesome</a> is an open source-project created by Dave Gandy. Font released under the <a href="http://scripts.sil.org/OFL" rel="nofollow ugc">SIL OFL 1.1 license</a>. Code released under the <a href="http://opensource.org/licenses/mit-license.html" rel="nofollow ugc">MIT License</a>.</li>
</ul>
Links
<ul>
<li><a href="https://www.spacexchimp.com" rel="nofollow ugc">Developer website</a></li>
<li><a href="https://github.com/ArthurGareginyan/syntax-highlighter-for-postpage-html-editor" rel="nofollow ugc">Dedicated plugin page on GitHub</a></li>
<li><a href="https://wordpress.org/plugins/syntax-highlighter-for-postpage-html-editor/">Dedicated plugin page on WordPress.org</a></li>
</ul>

Syntax Highlighter for Post/Page HTML Editor

Does what it says, configurable, great options, never will set up a WP install without this. =]

Just great

Replaces the defaults WordPress Post/Page HTML Editor with an enhanced editor with syntax highlighting, line…

Simple Quick Tags vs Syntax Highlighter for Post/Page HTML Editor