BuddyPress example block: Put this two file into a `bp-example-block` folder before dropping it into `/wp-content/plugins/`

bp-example-block.php

<?php
/**
 * Plugin Name: BP Example Block
 * Plugin URI:  https://buddypress.org/
 * Description: Example of BuddyPress block.
 * Author:      The BuddyPress Community
 * Author URI:  https://buddypress.org/
 * Version:     1.0.0
 * Text Domain: buddypress
 * Domain Path: /languages/
 * License:     GPLv2 or later
 */

// Exit if accessed directly
defined( 'ABSPATH' ) || exit;

function bpeb_register_block() {
    wp_register_script(
        'bp-example-block',
        plugins_url( 'bp-example-block.js', __FILE__ ),
        array( 'wp-blocks', 'wp-element' )
    );

    register_block_type( 'bpeb/example-block', array(
        'editor_script' => 'bp-example-block',
    ) );
}
add_action( 'init', 'bpeb_register_block' );

buddypress-example-block.js

( function( blocks, element ) {
    var el = element.createElement;

    blocks.registerBlockType( 'bpeb/example-block', {
        title: 'BuddyPress example block',
        description: 'A BuddyPress example block to show how to be listed into the BuddyPress blocks category.',
        icon: 'buddicons-groups',
        category: 'buddypress',
        edit: function() {
            return el(
                'p',
                {},
                'BuddyPress blocks are stored into the BuddyPress blocks category.'
            );
        },
        save: function() {
            return el(
                'p',
                {},
                'BuddyPress blocks are stored into the BuddyPress blocks category.'
            );
        },
    } );
}(
    window.wp.blocks,
    window.wp.element
) );