Soli

<p>This plugin allows you to append a signature after every post. Some variables can be used, such as %post_title%, %post_link%, %bloginfo_name%, %bloginfo_url%, and so on. It supports multiuser.</p>


WP Post Signature

Works great for me

This plugin allows you to append a signature after every post. Some variables can be used.

Zakir Sajib

<p>The Author Signature plugin allows WordPress users to have signatures below every post and every page.<br />
There is an option to turn off the display on post and page.</p>
<h3>Features Request</h3>
<p>Send me your requests here: zakirsajib@gmail.com</p>


Author Signature

This plugin appends the author's signature to blog posts or/and pages.

WP Post Signature vs Author Signature