seothemes

HTML Widget adds a new widget that can be used for displaying any custom HTML in a easy to use way. The syntax highlighting makes the code clear and readable which makes your widgets easier to manage. Only users with sufficient capabilities can use all HTML elements, while users with limited capabilities can only use safe HTML that is allowed in posts.

HTML Widget

This plugin replaces the lost functionality that the updated Text widget took away and it ends up being better than the one coming into core in 4.8.1 by adding syntax highlighting and autocompletion.

Better than core

Adds a simple HTML widget with syntax highlighting for HTML, CSS and JS.

kartikaykanojia

A code syntax highlighter an easy to use source code embedding in wordpress with different(55) themes with 172 languages. 
It uses dynamic script loading to load only essential javascript to render code syntax highliting. 
It uses most powerfull open source library CodeMirror as engine.
Features
<ul>
<li>Dynamic script loading to minimize load time and http call</li>
<li>172 language support</li>
<li>172 shortcodes</li>
<li>Shortcode picker in editor</li>
<li>Lightweight language selector</li>
<li>Multiple Theme support</li>
<li>55 Themes</li>
<li>Theme manager</li>
<li>Theme uploader (Upload your own theme)</li>
<li>Compatible with all WordPress themes</li>
<li>Fast and secure</li>
<li>Cross browser compatible</li>
<li>Line numbering</li>
<li>A powerful, composable language system</li>
<li>Bracket and tag matching</li>
<li>Line selector</li>
<li>Able to resize to fit content</li>
</ul>
Minimum system requirements:
<ul>
<li><a href="https://php.net" rel="nofollow ugc">PHP</a> version 5.2 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://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>
Credits
<ul>
<li>The banner of plugin is a copyrighted image created by the <a href="http://www.briskjab.com" rel="nofollow ugc">Briskjab</a>. (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>
</ul>

Code Syntax Highlighter

A simple dynamic loading syntax highlighter.Supports 172 languages, 172 shortcodes and 55 themes.

HTML Widget vs Code Syntax Highlighter