Fredrik Stigsson

This plugin uses <a href="https://github.com/googlearchive/code-prettify" rel="nofollow ugc">Google Code Prettify</a> with customized styling. This plugin uses the default skin, custom styling has been applied to show line numbers and to prevent line-breaks. The wp-code-block is styled by the theme (borders, background color and more), the contents of the pre-block is styled by css in the plugin.

Annytab Code Prettify

A lightweight plugin that automatically prettifies code in [pre] tags, with linenumbers and without line-breaks.

garethgillman

This plugin prettifies/beautifies/highlights source code placed inside <code><pre class="prettyprint"></code> tags. It is a light plugin with only 2 files.
New in 3.2.2 – use the hammer icon in the editor to paste your code and automatically have it converted to pretty code.

Syntax Highlighter Lite

This plugin prettifies/beautifies/highlights source code placed inside `` tags. It is a light plugin with only 2 files.

Annytab Code Prettify vs Syntax Highlighter Lite