ThemeShock

<p>Custom 404, helps you customize your 404.<br />
From the dashboard options you’re able to modify the background, the image and the fonts color and style.</p>
<p>This page will show users the last post on your site, so that they may choose to follow one of this instead of leaving your page.</p>
<h3>Features</h3>
<ul>
<li>Customizable background</li>
<li>Several Patterns</li>
<li>Multiple fonts</li>
<li>24 additional images.</li>
<li>5 Different languages</li>
</ul>


Custom 404 Error Page: Unilimited designs and colors

Custom 404, creates a 404 page that is set to the default one of your WordPress installation.
This page is fully customizable from the dashboard.

Uffe Fey

<p>This plugin enables safe mode for WordPress. This means:</p>
<ul>
<li>No plugins will be loaded.</li>
<li>A default theme will be temporarily activated (if it is installed).</li>
</ul>
<h4>Why is this useful?</h4>
<p>Whenever something’s wrong with a WordPress site, the first rule of thumb is to disable plugins and revert to the default theme if possible. Depending on the nature of the error, that is not always an option. The back end (dashboard) may also be down or you may not have FTP access to manually disable plugins and themes.</p>
<p><strong>Enter Safe Mode</strong>. Safe Mode will completely disable all plugins and the active theme temporarily for a single page view – ultimately enabling you to log in and remove the offending plugin. (This is not guaranteed to work in all scenarios, please read the disclaimer)</p>
<h4>How does it work?</h4>
<p>If your site crashes due to an upsetting plugin or theme, all you have to do is add a querystring parameter to the URL. Doing that will temporarily disable all plugins for that single page view, as well as temporarily activate a default theme if one is installed.</p>
<p>Let’s say you’re the owner of www.example.com. To enable safe mode for one particular page, you add this to the URL: “?safe_mode=1”.</p>
<p>Bear in mind that you have to do this for every view. The querystring parameter isn’t carried on automatically. So, for instance:</p>
<ul>
<li>If you need to log in, go to: www.example.com/wp-admin/?safe_mode=1</li>
<li>If you need to go to plugin management, go to: www.example.com/wp-admin/plugins.php?safe_mode=1</li>
<li>If you need to go to theme management, go to: www.example.com/wp-admin/themes.php?safe_mode=1</li>
</ul>
<p>When you go to plugin management, all plugins will seem to be deactivated (due to the way Safe Mode works), but you’ll still be able to explicitly deactivate each plugin. Just use the “Deactivate (safe mode)” option.</p>
<h4>What are default themes?</h4>
<p>By default theme, I’m referring to the themes that ships with WordPress, you know, the Twenty “something” ones.</p>
<p>The plugin checks if any of these themes are installed, and if so, activates the first theme it encounters. Thus I highly recommend that you keep one of those themes installed at all times. If you don’t, safe mode will keep your current active theme, and that theme may just be the offender – leaving safe mode useless. Keep this in mind.</p>
<h4>Disclaimer</h4>
<p>This plugin will be able to handle many scenarios, but not all. If your site’s crash is caused by a database crash, or something that simply brings down the PHP parser, like a call to an undefined function, Safe Mode won’t be able to do anything about that.</p>


Safe Mode

I love using Health Check. And starting today I love this as well. 
Using a URL parameter for selective application is ***** alone. 

Keep it up!

Fantastic.

Makes it possible to enable safe mode for WordPress. In safe mode, plugins will not be loaded and the default theme (if installed) will be activated.

Custom 404 Error Page: Unilimited designs and colors vs Safe Mode