michielve

There are other good syntax highlighter plugins, but I wanted something simple and fast and 
be able to add the highlight classes with a select box in the TinyMCE editor.
I added some default languages: Javascript, PHP, Python, C, C#, VB.NET, SQL and CSS but you can 
easily add other ones.

Simple Fast Highlighter

Fast syntax highlighter written in Javascript.

kioub

With support for the new block editor in WordPress 5.0!
SyntaxHighlighter Amplified allows you to easily post syntax-highlighted code to your site without losing its formatting or making any manual changes. It uses the <a href="https://github.com/scrivo/highlight.php" rel="nofollow ugc">highlight.php package by Geert Bergman</a> to render code on the server-side so it has no depedencies on extrenal Javascript libraries thus is compatible with AMP pages.
For a live demo, see <a href="https://www.javacodegeeks.com/syntaxhighlighter-amplified/" rel="nofollow ugc">this demo page</a>.
For a list of supported languages (most widely used languages are supported), see the <a href="http://en.support.wordpress.com/code/posting-source-code/" rel="nofollow ugc">WordPress.com support document</a>.
Development of this plugin is <a href="https://github.com/kioub78/syntaxhighlighter-amplified" rel="nofollow ugc">on GitHub</a>. See <a href="https://github.com/kioub78/syntaxhighlighter-amplified/issues" rel="nofollow ugc">list of current issues</a> with the plugin. Please feel free to file any additional issues or requests that you may come across. <a href="https://github.com/kioub78/syntaxhighlighter-amplified/pulls" rel="nofollow ugc">Pull requests</a> are welcome.
Translation of the plugin into different languages is on the <a href="https://translate.wordpress.org/projects/wp-plugins/syntaxhighlighter-amplified" rel="nofollow ugc">translation page</a>.
<h4>CREDITS</h4>
This is a fork of <a href="https://github.com/Automattic/syntaxhighlighter" rel="nofollow ugc">SyntaxHighligher Evolved</a> by <a href="https://alex.blog/" rel="nofollow ugc">Alex Mills</a> (Viper007Bond), which is also <a href="https://wordpress.org/plugins/syntaxhighlighter/" rel="ugc">available on WordPress.org</a>. Copyright (c) 2018 Alex Mills. Licensed under GPL 2.0 or later.
<a href="https://github.com/scrivo/highlight.php" rel="nofollow ugc">highlight.php</a> is released under the BSD 3-Clause License. Copyright © 2006-2013, Ivan Sagalaev (maniac@softwaremaniacs.org), highlight.js (original author). Copyright © 2013, Geert Bergman (geert@scrivo.nl), highlight.php

SyntaxHighlighter Amplified

Easily post syntax-highlighted code to your site without having to modify the code at all. Compatible with AMP pages.

Simple Fast Highlighter vs SyntaxHighlighter Amplified