Jonas Hjalmarsson

A single shortcode you can drop into any post, page, or text widget to get a click-to-expand “read more” toggle. The output is a native HTML <code><details></code> element styled with a small inline stylesheet — nothing else.
The point is the absence of features. There is no settings page, no animation library, no editor block panel with twelve toggles. If you need a read-more on one paragraph in one post, you do not want a plugin that wants to manage your whole site.
Usage:
<pre><code>[expand title="My title"]
The content goes here.
<img src="even-images-can-go-in-here.jpg" />
And wrap up with a closing expand tag.
[/expand]
</code></pre>
Supports a custom CSS class via <code>[expand class="my-class"]</code> and works with WordPress oEmbeds and other shortcodes nested inside.

Simple Expand – Lightweight Read more toggle

Adds an [expand] shortcode that wraps content in a native HTML `` toggle. No JavaScript, no settings page, no bloat.

Nick Cousins

<h4>Because “read more” isn’t good enough</h4>
Turn your “More” links into a bespoke call-to-action for each post. Rather than have “Read more” or “[…]” after your excerpt, you could have “See Bob’s garden up close” in a post about a beautiful garden, or “Try our tasty sauce” in a bolognese sauce recipe.

ActionPress

Still works

Replace the [...] more link with custom text for each post, creating a specific call-to-action.

Simple Expand – Lightweight Read more toggle vs ActionPress