shawfactor

mattsenate

This plugin is can be used for petitions, events, or any verified list and as far as I know is unique in WordPress.
Creating a petition/list/signup is as easy as adding a shortcode to a post or page (or CPT). From there additional editors are available to configure easch aspect of the sign up. Everything is completely self hosted and all list members become users of your site (not a third parties).
Available shortcodes:
[lh_signing_form] (enable signatories on any post, page, or custom post type)
Unconfirmed signatories: [lh_signing_unconfirmed_count]
Confirmed signatories: [lh_signing_confirmed_count]
Total signatories: [lh_signing_total_count]
[lh_signing_unconfirmed_list] (unformated list)
[lh_signing_confirmed_list] (unformated list)
You can customise the display of the signing form ([lh_signing_form]) via a number of shortcode arguments more information is available <a href="https://lhero.org/portfolio/lh-signing/" title="Additional Plugin documentation" rel="nofollow ugc">here</a>

LH Signing

LH Signing allows you to create configurable validated lists like petitions or event sign ups. It is the only self hosted solution in WP

MailboxValidator

This email validation plugin helps you to block disposable email, free email, invalid email or role-based email from using your services or input form.
It helps to block spam, temporary emails and invalid email address messing around your site. You don’t have to master the hard part of adding shortcode into page source to use this plugin, but to activate, configure and you’re ready to prevent all spam signups from invalid email addresses.
You can <a href="https://www.mailboxvalidator.com/plans#api" title="MailboxValidator API key sign up" rel="nofollow ugc">sign up for a free API key</a> at mailboxvalidator.com, that will allow you to validate up to 300 emails every month for free!
<h4>Supported Plugins</h4>
<ul>
<li>Contact Form 7</li>
<li>MailChimp</li>
<li>Formidable forms</li>
<li>WooCommerce</li>
<li>JetPack comments and contact form</li>
<li>Profile Builder</li>
<li>Ultimate Member registration form</li>
<li>Users Ultra registration form</li>
<li>Theme My Login</li>
<li>WP-Members</li>
<li>Paid Membership Pro</li>
<li>Visual Form Builder</li>
<li>Easy Digital Downloads registration form</li>
<li>and other plugins that yet come under our radar</li>
</ul>
<h4>Key Features</h4>
<ul>
<li>Accurate email verification result</li>
<li>Block invalid email.</li>
<li>Block disposable email.</li>
<li>Block free email.</li>
<li>Block role email.</li>
<li>Support domain blacklisting.</li>
</ul>
This email verification plugin needs a MailboxValidator API key to work. You can get a free API from <a href="https://www.mailboxvalidator.com/plans#api" title="MailboxValidator API key sign up" rel="nofollow ugc">MailboxValidator</a>.

MailboxValidator Email Validator

Email verification for WordPress forms. Block disposable, block spam, block invalid email, block free email and role-based email.

LH Signing vs MailboxValidator Email Validator