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 verification plugin enables Contact Form 7 users to validate email address before sending the form. It uses MailboxValidator email validation service to check if an email address is disposable email address or free email address in order to block invalid email from signing up. 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 with 300 FREE email validation credits every month!
Note: Contact Form 7 must be installed and activated before using this MailboxValidator email validation plugin.
Key Features
<ul>
<li>Accurate email verification result.</li>
<li>Support invalid email validation.</li>
<li>Support disposable email validation.</li>
<li>Support free email validation.</li>
<li>Support role-based email validation.</li>
<li>Support domain blacklisting.</li>
<li>Support trusted domain whitelisting.</li>
<li>Enable you to block the users from message sending if failed in validation.</li>
</ul>
This plugin need a MailboxValidator API key to work. You can get it from <a href="https://www.mailboxvalidator.com/plans#api" title="MailboxValidator API key sign up" rel="nofollow ugc">here</a>.

Email Validator for Contact Form 7

Email validation for Contact Form 7. Reduce registration spam with invalid email, block disposable and block free email.

LH Signing vs Email Validator for Contact Form 7