Marc Tönsing

Ipstenu (Mika Epstein)

This plugin displays the most basic of quicktag buttons on your comment forms, using the Quicktag API built into WordPress (as of 3.3). No jQuery needed.
Contribute on <a href="https://github.com/mtoensing/marctv-quicktags" rel="nofollow ugc">GitHub</a>.

Simple Comment Quicktags

Simple and clean

Make commenting easier with bold, italic, add link and quote buttons on top of the form.

diekleinehexe

This plugin will add a button to both the visual and HTML WordPress Editor panel allowing you to easily insert code for WP-Syntax. WP-Syntax is a syntax highlighting plugin for WordPress which can be downloaded from https://wordpress.org/extend/plugins/wp-syntax/
Usage
<ol>
<li>Select the text you want to have highlighted by WP-Syntax</li>
<li>Click the button pre (WP-Syntax) in HTML editing mode or the icon with colored lines in visual editing mode</li>
<li>Enter the language and starting line separated by a comma. The later is optional.</li>
</ol>

WP-Syntax Editor Integration Plugin

Adds new buttons to the visual and html editor window which allow to use WP-Syntax.

Simple Comment Quicktags vs WP-Syntax Editor Integration Plugin