sander85

This plugin allows to block spammers with the following options:
<ul>
<li>Block spammers by IPs (supports wildcards).</li>
<li>Block IPs that have posted comments marked as spam.</li>
<li>Block comments that contain bad words.</li>
</ul>
Additional options:
<ul>
<li>If comment contains bad words, add the spammers IP into the blacklist.</li>
<li>When deleting spam, add IPs of spam comments into the blacklist.</li>
<li>Similar entries in the blacklist are merged automatically.</li>
</ul>

Block Spammers

Block spammers from submitting comments, by IPs or by bad words.

MythThrazz

The plugin is very simple and it doesn’t come with any changable options.
The only feature it has is ability to detect the AdBlock (tested on Chrome AdBlock extension) and defines the HTML class allowing to control the visibility of 
the elements on your page based on the detection result eg. you can show an element on your page only if AdBlock is detected, or hide it.

Tiny Simple AdBlock Detector

Detects AdBlocking software and allows to display some html based on detection result. Word for AdBlock for sure. Should work for others.

Block Spammers vs Tiny Simple AdBlock Detector