gptmade

The Image Modal plugin adds a modal lightbox effect to images within the post content, allowing users to view larger versions of images without leaving the post.
This plugin requires NO settings, NO subscriptions, NO trials or pro versions. It just works out of the box with any image on the content of your posts or pages, either if it was Attached to the media library or just pasted from clipboard.
When an image is clicked, a modal box will appear with the larger version of the image. Dismiss the modal box with the close button or clicking on the modal’s background.
<h3>Requirements</h3>
NONE, but to show a pointer cursor when hovering on the images, his plugin requires that your content div in your theme has the class “.entry-content”. Chances are that this is the case if you are working with a relatively modern theme.
<h3>Licensing</h3>
This plugin is released under GPLv2.
<h3>Author</h3>
gptmade.com

Image Modal

This plugin adds a modal lightbox effect to images within the post content, allowing users to view larger versions of images without leaving the post.

Piyush Asthana

Asap – Popups Studio lets you create and manage multiple popups from the WordPress admin. Each popup has its own settings for when and where it appears.
Features:
<ul>
<li>Multiple popups – Create as many popups as you need; each is a separate post with its own content and settings.</li>
<li>Display control – Enable/disable per popup; choose trigger (page load with delay, scroll percentage, or exit intent).</li>
<li>Visibility – Show on all pages, pages only, posts only, or selected pages.</li>
<li>Show once – Limit to once per session, per day, per week, or per month using cookies.</li>
<li>Custom HTML – Optional custom HTML (replacing the main editor content) with allowed tags only; no script insertion.</li>
<li>Animations – None, fade in, or slide up.</li>
<li>Width – Set popup width in pixels or percentage.</li>
<li>Quick toggle – Enable/disable popups from the list screen with a toggle switch.</li>
</ul>
For site-wide or per-page custom CSS, use the WordPress Customizer or theme/block editor. Uses the block editor (or classic editor) for popup content; optional custom HTML overrides that for a single popup. All user-facing strings are translation-ready (text domain: <code>asap-popups-studio</code>).

Asap – Popups Studio

Create and manage multiple custom popups with individual settings and display rules.

Image Modal vs Asap – Popups Studio