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.

Ben Lobaugh (blobaugh)

iwongu

This plugin is a syntax highlighter for source code. It uses GeSHi as fontifier engine.
<h4>Usage</h4>
<ol>
<li>Put the code snippet in a “` tag.</li>
<li>Add the lang attribute to the code tag like the following. <code><code lang="php"></code> </li>
<li>Add the lineno attribute to the <code><code></code> tag after the lang tag if you wish to start at a line other than 1. <code><code lang="cpp" lineno="42"></code></li>
<li>If you do not add lang attribute, the <code><code></code> tag is handled normally.</li>
<li>If you want to have border, add the style like the following to your .css file. <code>code { border: 1px dotted #ccc; padding: 0.2em 0.5em; }</code></li>
<li>You can use following languages in lang. <code>abap, actionscript, ada, apache, applescript, asm, asp, autoit, bash, blitzbasic, bnf, c, c_mac, caddcl, cadlisp, cfdg, cfm, cpp-qt, cpp, csharp, css-gen, css, d, delphi, diff, div, dos, dot, eiffel, fortran, freebasic, genero, gml, groovy, haskell, html4strict, idl, ini, inno, io, java, java5, javascript, latex, lisp, lua, m68k, matlab, mirc, mpasm, mysql, nsis, objc, ocaml-brief, ocaml, oobas, oracle8, pascal, per, perl, php-brief, php, plsql, python, qbasic, rails, reg, robots, ruby, sas, scheme, sdlbasic, smalltalk, smarty, sql, tcl, text, thinbasic, tsql, vb, vbnet, vhdl, visualfoxpro, winbatch, xml, xpp, z80</code> </li>
</ol>
Note: Version 1.9 adds support for <code><code></code> tags, however to ensure backwards compatibility support for the <code><pre></code> tag will not be removed.
<h3>Known issues</h3>
<ol>
<li>Because this plugin uses regular expression to match string range from <code><code lang="some"></code> to “`, you can’t use <code></code></code> in your code snippet. If you must put the <code></code></code> tag, you can put a space between <code><</code> and <code>/code></code> like <code>< /code></code>. The <code>< /code></code> is converted to <code></code></code> automatically by plugin.</li>
<li>If you want to change the style, you should modify the plugin source file. 😛</li>
</ol>

CodeHighlighter

This plugin is a syntax highlighter for source code using GeSHi.

Easy Code Highlighter vs CodeHighlighter