Eric McNiece

EMC2 Popup Disclaimer uses Fancybox (http://fancybox.net) to display the popup, and jQuery-cookie (https://github.com/carhartl/jquery-cookie) to detect user session. Creates a cookie named “emc2pdc” that can be viewed with regular developer tools.
Easy to use! By default the script is added to the wp_footer action and will work quietly. You can also force the display on pages via shortcode or function call: 
Shortcode: <code>[emc2pdc id="42"]</code> 
 -or- 
Function: <code><?php emc2pdc_force( $atts=array(), $force=NULL, $id=NULL ); ?></code>
Check the demo at http://popup.emc2innovation.com !
To Do list:
<ul>
<li>Add No-JS fallback support</li>
<li>Create a selection of button themes</li>
<li>Add support for different lightbox types</li>
<li>Improve handling, add PHP cookie support</li>
</ul>
Known bugs:
<ul>
<li>Recursive post shortcode call results in chaos</li>
</ul>
<h3>Configuration</h3>
EMC2 Popup Disclaimer will work straight out of the box. There’s a few options available from within WordPress, and future releases will feature themeable options.
Settings can be found in these locations:
<ul>
<li>/wp-admin/options-general.php?page=emc2-popup-disclaimer/emc2pdc-admin.php (Default settings)</li>
<li>/wp-content/plugins/emc2-popup-disclaimer/js/emc2pdc.js (Fancybox, jQuery-cookie settings)</li>
</ul>
The settings page is straightforward except for perhaps the “Restrict operation to directory:” setting. This is the operational directory of the jQuery cookie plugin – default is ‘/’, which is your entire site. To specify operation for a certain directory, type it here like ‘/store’. More jQuery-cookie settings can be found at https://github.com/carhartl/jquery-cookie.
Things of note:
<ul>
<li>Specify post ID using shortcode is optional ? if blank, it will use ID# from settings</li>
<li>Shortcode / function call will override wp_footer action</li>
<li>Debug mode will output visible settings on every included page</li>
<li>Setting an ID equal to the page you?re calling from results in mass chaos! If you set the shortcode [ emc2pdc id=”10″ ] on post ID 10 it seems to freak out a bit.</li>
</ul>

EMC2 Popup Disclaimer

EMC2 Popup Disclaimer places a specified post into a lightbox and adds buttons so that your visitors must click through to agree to your terms!

Freemius

Hook Labs

Terms Gate lets you require visitors to agree to your terms, privacy policy, or any custom agreement before they can view specific posts or pages. Great for privacy, compliance, or content gating.
Features: 
– Require agreement on selected posts or pages 
– Custom agreement forms (use any content or shortcode) 
– Remembers user consent with cookies 
– Easy admin interface for managing agreements 
– Bulk assign or unassign agreements (Premium) 
– Supports Gutenberg and Classic Editor 
– SEO Friendly – common bots and crawlers are omitted from terms agreement pages
Premium Features: 
– Remove the 3-page/post limit 
– Bulk assign/unassign agreements to all posts or pages 
– Priority support
<h3>License</h3>
This plugin is free software, released under the GPLv2 or later.
<h3>Credits</h3>
Developed by Hook Labs.
<h3>Support</h3>
For support, visit https://your-site.com/support or use the WordPress.org support forum.

Terms Gate

Require users to agree to your terms before viewing selected WordPress pages or posts. Simple, flexible, and GDPR-friendly.

EMC2 Popup Disclaimer vs Terms Gate