ReorMadrid

To use it, you must use the [code] shortcode like this:
PHP Code Example:
[easycode] 
< ? php 
e cho “Hi, world!”; 
 ? > 
[/easycode]
In the admin menu, you have options to change the background colors, button colors, language and more.

Easy Code Highlighter

Displays code with syntax highlighting using Prism.js, real line numbering, and a copy button.

Peter Booker

(note: Gutenberg Editor Required)
A syntax / code highlighter Gutenberg block. Paste your code into the block, set the language and see your code highlighted exactly like it will display on the frontend.
<h4>Features</h4>
<ul>
<li>Syntax highlighting block for the Gutenberg Editor</li>
<li>Switch between editor and preview, see exactly what will appear on the frontend.</li>
<li>Supports 121 languages, listed <a href="https://codemirror.net/mode/" rel="nofollow ugc">here</a>.</li>
<li>2 Themes, VSCode Dark+ and Github, see the screenshots below. (more coming soon)</li>
<li>Static HTML output, no frontend scripts or user tracking.</li>
</ul>

Kebo Code

Lightweight syntax / code highlighter which outputs plain HTML, no bloat or JavaScript.

Easy Code Highlighter vs Kebo Code