Bjørn Johansen

This is a WordPressified version of the excellent, lightweight (for real!) imageLightbox.js (MIT-licensed) by Osvaldas Valutis (http://osvaldas.info/image-lightbox-responsive-touch-friendly)
This is his introduction to the lightbox: 
“As for the image lightboxes, I have always lacked simplicity for them. I mean not only the visual design, but the overall experience: from implementation to UX. All due respect, but I have never liked any of these light-fancy-face-boxes. They all were solving problems that just don’t exist: lots of unwanted features by default, total mess in markup, no native behavior for touch screens. I was working on a project and needed an image lightbox that solves these problems. I needed a lightbox only for images, not video, text, and iframes at once. I made ImageLightbox.js.”
This version autodetects all links to image files and opens them in the lightbox.
For your “install, activate and go”-convenience, this plugin comes with a minimal CSS that easily can be deactivated and/or replaced.
The plugin can also be themed to your liking. An example theme is available here: https://github.com/bjornjohansen/imagelightbox-theme-smooth
Please let me know if you have any issues. Fastest way to get a response is by Twitter: https://twitter.com/bjornjohansen

imageLightbox

Image Lightbox, Responsive and Touch‑friendly.

Ryan Edmunds

SuperLight CPT Manager is a minimalist WordPress plugin that lets administrators create Custom Post Types without clutter or bloat.
Each CPT automatically:
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Registers itself with WordPress (visible in menus and REST API)
</li>
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Supports basic post features (title, editor, thumbnail, excerpt)
</li>
<li>
Comes with a unique shortcode (e.g. <code>[superlight_cpt slug="book"]</code>)
</li>
</ul>
There are no extra scripts, no custom tables, and no unnecessary settings — just pure, clean functionality in under 200 lines of PHP.
Features
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<li>
Add, import/export, or delete custom post types on the fly
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Each post type gets its own shortcode
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Works instantly with Query Loop and block editors (<code>show_in_rest</code> enabled)
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All CPTs stored in a single WordPress option (<code>superlight_cpts</code>)
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<li>
No dependencies, no setup, no nonsense
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</ul>
<h3>License</h3>
This plugin is licensed under the GPLv2 or later.

SuperLight CPT Manager

Create and manage custom post types instantly. Each CPT gets its own shortcode.

imageLightbox vs SuperLight CPT Manager