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.

darrinb

Easily include raw markup languages (HTML, CSS, PHP, etc.) in comments using custom quicktags. No need to encode, the filter does it for you. Creates convenient “encode” buttons for comment authors in the HTML editor.
Also adds basic quicktag buttons on the comment forms, using the Quicktag API built into WordPress (as of 3.3).

Simple Comment Quicktags vs WP Comment Encode