Richard Bush

The 42U Jetpack Booster adds redirect tags and HTML email templates to Jetpack Contact Forms.
To add a redirect to your Jetpack Contact Form, just add a text field named “redirect” to your form. It will be hidden on display.
From the HTML view, set the default value to the location where you would like the form to redirect after submission.
[contact-field label=”redirect” type=”text” default=”/thanks/” /]
Note: you must replace the default each time after editing the form with the Jetpack WYSIWYG editor. The value is not saved by Jetpack.

42U Jetpack Booster

The 42U Jetpack Booster adds redirect tags and HTML email templates to Jetpack Contact Forms.

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.

42U Jetpack Booster vs reCAPTCHA Jetpack