Barry Carlyon

This plugin adds extra bits an pieces to <a href="https://wordpress.org/extend/plugins/jetpack/" rel="ugc">WordPress Jetpack</a>
Previous called “Jetpack Extras” renamed at request of Jetpack Team to “Custom Tweaks for Jetpack”
Which includes the following additions:
<ul>
<li>
Ability to control button placement, above, below, or both of the post content, with separate options for the archive page and content display page
</li>
<li>
Twitter Button added Related (username/optional description format)
</li>
<li>Adds the ability to make the Twitter button share the WP.me url, if that JetPack module in use, <a href="http://skipsloan.com/?p=175" rel="nofollow ugc">As suggested by SkipTweets on Twitter</a></li>
</ul>
Currently removed is:
<ul>
<li>Ability to turn on/off the <a href="https://dev.twitter.com/docs/tweet-button#optout" rel="nofollow ugc">DNT Twitter</a> button mode – it is difficult to add without editing chunks of the core</li>
</ul>

Custom Tweaks for Jetpack by BarryCarlyon

Extras for WordPress Jetpack. Tested up to Jetpack 3.4.1

bozdoz

<a href="https://wordpress.org/plugins/jetpack/" rel="ugc">Jetpack</a> makes it easy to add contact forms to your WordPress site, but you may want a simple way to add a <a href="https://www.google.com/recaptcha/" rel="nofollow ugc">Google reCAPTCHA</a> to prevent spam. This plugin will manipulate the Jetpack <code>[contact-form]</code> shortcode to prepend the Google script, add a button, and parse the response.
This plugin allows both reCAPTCHA v2 and invisible reCAPTCHA (see screenshots and choose whatever works for you!).
Shoot me a question about it on Twitter: <a href="https://www.twitter.com/bozdoz/" rel="nofollow ugc">@bozdoz</a>.
This plugin is open source on <a href="https://github.com/bozdoz/wp-plugin-recaptcha-jetpack" rel="nofollow ugc">GitHub</a>!

reCAPTCHA Jetpack

A simple plugin that adds a Google reCAPTCHA to the Jetpack contact form. Requires the Jetpack plugin.

Custom Tweaks for Jetpack by BarryCarlyon vs reCAPTCHA Jetpack