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.

stevenkellow

A simple plugin that allows you to copy paragraphs from your site’s main content to the clipboard to use elsewhere.
<h3>FAQ / Info</h3>
The plugin works straight out-of-the-box, so once you’ve installed you’re ready to go!
If you want to change the image that appears when hovering over content before copying, enter your own in the img folder of this plugin and rename it click-to-copy.png.

Click to Clipboard

A simple plugin that allows you to copy paragraphs from your site's main content to the clipboard to use elsewhere.

Carmo Copy to Clipboard vs Click to Clipboard