Dabuuker

Show content in a modal after page load.
Usage:
Select ‘SN Popup’ from the admin menu, then Add New. Type a name for the popup and insert any content you like. If you’re done, click Publish.
Now find a page or post you’d like to see the popup on and edit it. There should be a new metabox called ‘SN Popup’, choose the settings you want and hit Update, then view your page.
Video: https://www.youtube.com/watch?v=t6lt6v3fuEQ
To change the styling of the modal, you can override its styles in your theme’s css. Or for more advanced styling you can dequeue the default css and replace it with your own.
For reference, the default unminified version of the css is located at /plugins/sn-popup/vendor/featherlight-1.3.4/src/featherlight.css
To dequeue the old css and enqueue your own, add something like this to your functions.php:
<pre><code>add_action('wp_enqueue_scripts','remove_featherlight_css'); function remove_featherlight_css(){ wp_dequeue_style('sn-featherlight'); wp_enqueue_style('featherlight-new-css','/path-to-new-css'); } </code></pre>

Soronet Popup

Tsubu

ReformBox extends WordPress Lightbox functionality beyond images. It currently supports Group, Paragraph, and Video blocks with poster images directly, while delegating Image lightbox behavior to WordPress core. For <code>core/image</code>, ReformBox only syncs the sidebar toggle with core lightbox settings.
<a href="https://github.com/tbshiki/reformbox" rel="nofollow ugc">This plugin is developed on GitHub.</a>
Supported Blocks:
<ul>
<li>Image Block – Uses WordPress core lightbox behavior (ReformBox panel toggles core <code>lightbox.enabled</code>)</li>
<li>Video Block – Opens in a lightbox when a poster image is set (poster acts as the click trigger)</li>
<li>Group Block – Supports both <code>same</code> mode (same content in page + modal) and <code>split</code> mode (separate Preview/Modal direct child Group slots)</li>
<li>Paragraph Block – Click to open itself in a lightbox</li>
</ul>
Features:
<ul>
<li>No-code lightbox creation via block editor controls</li>
<li>Core-first image lightbox integration (<code>core/image</code>)</li>
<li>Core-aligned overlay markup for custom lightboxes</li>
<li>Core-aligned zoom animation</li>
<li>ESC key and overlay click to close</li>
<li>Accessible (ARIA attributes, focus management, keyboard navigation)</li>
<li>Group split mode with Preview/Modal slot mapping</li>
<li>Safe split fallback: if no Modal slot is assigned, Preview content is used</li>
<li>Lazy-loaded assets (CSS/JS only loaded when needed)</li>
<li>Self-lightbox videos defer preload/autoplay until opened</li>
<li>Core image workflow integration without overriding core image rendering</li>
<li>Global overlay background color and opacity controls in Settings > ReformBox</li>
<li>Plugin list row includes a Settings action link for quick access</li>
<li>Lightweight and performant</li>
</ul>

ReformBox

Universal Lightbox for WordPress – lightbox support for Group, Paragraph, Video blocks with poster images, and core Image workflows.

Soronet Popup vs ReformBox