Brandon Fenning

Since the vast majority of WordPress spam is automated in nature, the goal of BotBlocker is to block comment spam bots and not hinder users. This is accomplished through the use of honeypot technology, which tricks the spambot into identifying itself by performing actions that a human could not.
BotBlocker’s features include:
<ol>
<li>Works out of the box to block spam</li>
<li>Automatically stops spam-bots from commenting</li>
<li>Zero hindrance to users: no CAPTCHAS, math questions, passwords or extra input required</li>
<li>Zero false positives and ignores registered users</li>
<li>Can be configured to completely block spam-bots or flag comments as spam</li>
<li>Spam detection messages can be easily adjusted</li>
<li>No javascript or cookies required</li>
<li>Hooks into <code>wp-comments-post.php</code> to prevent spam-bots from directly submitting spam comments</li>
<li>Should work fine with most customized comment forms</li>
<li>No API keys required</li>
</ol>
http://www.lform.com/botblocker/ for more information.
Plugin by <a href="http://www.lform.com/" rel="nofollow ugc">LFORM, a web design company</a> in New Jersey.

BotBlocker

Kills spam-bots, leaves humans standing. No CAPTCHAS, no math questions, no passwords, just spam blocking that stops spam-bots dead in their tracks.

Umair Saleem

Easily create and add forms to WordPress. Fields are easy to add, remove, and re-order. The contact form will let the user send emails to a site’s admin, and also send a meeting request to talk over phone or video.
Features: easy form edit, multiple forms, confirmation emails, no templates to mess with, and an option to redirect visitors to any URL after the message is sent. Includes CAPTCHA and Akismet support to block spammers. Spam is no longer a problem. You can add extra fields of any type: text, textarea, checkbox, checkbox-multiple, radio, select, select-multiple, attachment, date, time, hidden, password, and fieldset.
<ul>
<li><a href="http://www.easysoftonic.com/" rel="nofollow ugc">Powered By Easy Softonic</a></li>
<li><a href="https://downloads.wordpress.org/plugin/easy-softonic-contact-form.zip" rel="nofollow ugc">Download WordPress Plugin Version</a></li>
</ul>
<h4>Help Keep This Plugin Free</h4>
If you find this plugin useful to you, please consider <a href="http://www.easysoftonic.com/contact-page/" rel="nofollow ugc">making a donation</a> to help contribute to my time invested and to further development. Thanks for your kind support! – <a href="https://profiles.wordpress.org/umairsaleem/" rel="nofollow ugc">Umair Saleem</a>
<h3>Credits</h3>
<ul>
<li><a href="http://www.easysoftonic.com/" rel="nofollow ugc">Umair Saleem</a> – Plugin Author / Lead programmer</li>
<li><a href="http://www.easysoftonic.com/" rel="nofollow ugc">Umair Saleem</a> – Plugin programmer</li>
</ul>

WP Contact Form

An easy and powerful form builder that lets your visitors send you email. Blocks all automated spammers. No templates to mess with.

BotBlocker vs WP Contact Form