brianFormstack

jeremyformstack

noahwesley

mmattax

Formstack’s <a href="https://www.formstack.com/integrations/wordpress?utm_source=wordpress.com&utm_medium=referral&utm_campaign=integrations" rel="nofollow ugc">WordPress form plugin</a> makes it quick and easy to embed contact forms, lead generation forms, payment forms, and more on your WordPress blogs and websites. Build customized online forms in seconds with our <a href="https://www.formstack.com/features/drag-and-drop?utm_source=wordpress.com&utm_medium=referral&utm_campaign=integrations" rel="nofollow ugc">drag-and-drop interface</a>, and integrate with <a href="https://www.formstack.com/integrations?utm_source=wordpress.com&utm_medium=referral&utm_campaign=integrations" rel="nofollow ugc">40+ third-party apps</a>, including Salesforce, MailChimp, and PayPal.
This plugin features two components:
<ul>
<li>Formstack Widget</li>
<li>Formstack Plugin</li>
</ul>
The Formstack widget allows you to embed Formstack web forms into your sidebar. The widget automatically optimizes the web form’s CSS to make your online forms fit and look great on your WordPress pages.
The Formstack Plugin adds a button to the TinyMCE editor that allows you to easily select the Formstack web form you wish to embed. Once a form is selected, a shortcode will be inserted into the editor, which will be converted to the selected form once your page or blog post is rendered.
This plugin supports the following shortcodes <code>[Formstack]</code>, <code>[formstack]</code>, and <code>[fs]</code>.
A Formstack account and API key are required. <a href="https://www.formstack.com/pricing?source=wp-plugin_utm_medium=pluginlisting" title="Free Online Forms" rel="nofollow ugc">Signup for free today!</a>

Formstack Online Forms

I'm not sure wrapping if this is just this version or all versions, but wrapping your site in an iframe doesn't constitute as a functioning plugin. 
Doesn't work on WP 4.5 as far as i'm concerned.



This doesn't work at all

This plugin allows you to easily embed Web forms built with Formstack's online form builder into your sidebar, pages, and posts.

captisaforms

<a href="https://captisa.com" rel="nofollow ugc">Captisa Forms</a> helps you create online forms with database storage.
Create online forms the easy way. Whether you’re looking to generate leads, conduct customer surveys, find applicants for a job, or register guests for an event, Captisa’s easy-to-use online form builder lets you build customized online forms to fit your exact needs in minutes
<h4>Main Features</h4>
<ul>
<li>Client Portal – Create Portals For Your Clients In Minutes. Share multiple forms with people outside of your organization.</li>
<li>Form Builder – Feature-rich easy-to-use form builder lets you build a customized online form to fit your exact needs in minutes.</li>
<li>Filters – Apply filters to view select records. Filtering is a useful way to see only the data you want displayed. You can use filters to display specific records in data entries. </li>
<li>Views – Define how a list of records for a specific form is displayed in the application, the columns to display, how wide each column should be, and how the list of records should be sorted.. </li>
<li>Dashboards – Dashboards act as a business intelligence tool by providing a snapshot of your data in various forms. You can use a dashboard to simultaneously present data from up to six charts.</li>
<li>Form Rules – Create form rules and recommendations to apply conditional logic without writing code. Form rules provide a simple interface to implement and maintain fast-changing and commonly used rules.</li>
<li>Duplicate Detection Rules – To maintain the integrity of your data, it’s a good idea to have rules in place to reduce duplicate records in the system.</li>
</ul>
Video tutorial to show you how to use Captisa Forms. 
<a href="https://www.youtube.com/channel/UCxdxy9cDZhBNGPaRq-i_hdg" rel="nofollow ugc">youtube</a>
Example: 
 [captisa id=”c11d2a2c-1ea7-40bb-b39d-9841fa0b8d7d” header=”true” prefill=”true”]

Captisa Forms Shortcode Plugin

Allows the use of a special short code [captisa] for embedding Captisa Forms.

Formstack Online Forms vs Captisa Forms Shortcode Plugin