João Carmo Pereira

This plugin will add a new copy to clipboard functionality to Gutenberg Code Block. 
It will add a copy button at the top right corner of the block. After clicked, it will select the text, copy to clipboard, and after copy it will deselect the copied text. No markup here.
This plugin makes use of two javascript libraries: 
Clipboard.js and Prism.js

Carmo Copy to Clipboard

This plugin will add a new copy to clipboard functionality to Gutenberg Code Block.

kontur.us

This Plugin will add your own ‘kontur Copy Code Button’ to any code-block on your site. When clicked, the code is copied to the clipboard. Works as well on mobile devices and the standard Gutenberg WP-Code-Block.
<h3>Set your own</h3>
<ul>
<li>button-text(s),</li>
<li>button-icon or image from the library,</li>
<li>class(es),</li>
<li>button-color, </li>
<li>button-text-color </li>
<li>the code text colorand “pre”-Background.</li>
<li>NOW: ALL color setting changes in a “live view” for easier styling.</li>
</ul>
<blockquote>
Want more 
 Please get involved and send uns your ideas. Via email or on the WordPress support page 🙂
</blockquote>
<a href="https://wordpress.org/support/article/managing-plugins/#installing-plugins" rel="ugc">More info on installing WP plugins</a>
Uninstalling
This plugin cleans up after itself. All plugin settings will be removed from your database when the plugin is uninstalled via the Plugins screen.

kontur Copy Code Button

Add your own 'kontur Copy Code Button' with your own icon, text, class, color and 'pre' background. Works as well with the Gutenbe …

Carmo Copy to Clipboard vs kontur Copy Code Button