Ben Doherty (Oomph, Inc)

Specify a list of tags to keep hidden: These tags will be invisible to users, 
such as in tag clouds or in post tags lists. This is useful when using tags to 
control behavior of your blog, or when you wish to maintain groupings of posts 
out of the public eye.
This does not prevent tag archives for hidden tags from being accessible, only 
hides tag links from tag lists and tag clouds.
Capable users (with the see_hidden_tags capability,) can see hidden tags in 
tag lists (but NOT tag clouds.) Hidden tags will receive the .hidden-tag class 
and are grayed out by default.

Oomph Hidden Tags

Hide certain tags from tag lists and tag clouds. Allow capable users to see hidden tags with the see_hidden_tags capability.

aterris

Hidden Login provides easy and discrete access to the admin functionality of your site. Pressing the set keystroke combination will activate Hidden Login, either displaying a modal login window or redirected to the admin area if you are already logged in. Visit the Hidden Login Options to set what pages are enabled (All Pages or Homepage Only) and set your desired activation keystroke combination.
<h3>License</h3>
The Hidden Login plugin was developed by Andrew Terris, and is provided with out warranty under the GPLv2 License.
Copyright 2010 Andrew Terris (@aterris – andrewterris.com)
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Hidden Login

Adds Keystroke Enabled Login Functionality

Oomph Hidden Tags vs Hidden Login