Marko Jakic

With this plugin you can add quick comments feature to any post. Just put “echo mjqc_comment_form( get_the_ID() , ‘Post quick comment’ )” , where first parameter is the ID of a post (e.g. within the loop), and the second one is anchor of a link (when click on this link, a form shows to post a quick comment).

MJ Quick Comments

With this plugin you can add quick comments feature to any post.

Jesper Johansen (jayjdk)

This plugin, Jayj Quicktag, allows you easily to add custom Quicktags to the post, page, or a custom editor.
It adds a settings page where you can add all the Quicktags you want (see Screenshots)
It supports both import and export of your Quicktags so you easily can add them to another WordPress install.

Jayj Quicktag

Allows you easily to add custom Quicktags to the post editor.

MJ Quick Comments vs Jayj Quicktag