Basic Gutenberg Block, with a RichText Component and a Button on a Toolbar thats logs to console - https://codeamp.com/interacting-with-gutenbergs-richtext-component-using-a-button/

basic-richtext-block.js

var el = wp.element.createElement;
const { __ } = wp.i18n; // Import __() from wp.i18n
const { registerBlockType } = wp.blocks; // Import registerBlockType() from wp.blocks
const { RichText, BlockControls, BlockFormatControls, AlignmentToolbar } = wp.editor;
const { Button, Dashicon, Tooltip, IconButton, Toolbar } = wp.components;
const { Component, Fragment } = wp.element;

//standard registerBlockType init
registerBlockType( 'my-block-plugin/block-w-insert-shortcode', {
	title: 'Block w Shortcode Button', //any title you like
	icon: 'universal-access-alt', //any dashicon or svg
	category: 'layout', //which category to appear under
	
	//schema of attributes
	attributes: {
		content: {
			type: 'array',
			source: 'children'
		}
	},
	
	//for adding things like a rich text editor, and controls - the editor
	edit: function( props ) {
		
		var content = props.attributes.content;
		
		//udpates the attribute `content` when the editor is updated,
		function onChangeContent( newContent ) {
			props.setAttributes( { content: newContent } );
		}
		
		//called when our custom toolbar button is pressed
		function onClickShortcodeButton( event ) {
			console.log("clicked insert shortcode button");
		}
		
		return [
			el( //the toolbar
				BlockControls, 
				{ 
					key: 'controls',
					controls: [
						{
							icon: 'edit',
							title: __( 'Insert Shortcode' ),
							onClick: onClickShortcodeButton
						}
					]
				}
			),
			el( //the richtext editor
				RichText,
				{
					key: 'editable',
					tagName: 'p',
					className: props.className,
					onChange: onChangeContent,
					value: content,
					keepPlaceholderOnFocus: true
				}
			),
		];
	},

	//for saving to the DB
	save: function( props ) {
		
		//save the content variable
		var content = props.attributes.content;

		return el( RichText.Content, {
			className: props.className,
			value: content
		} );
	},
} );