ACF Custom Block Category

hooks.php

<?php
/**
 * Adds a Custom Block category to the Gutenberg category list.
 * Use in acf_register_block_type ( [ 'category' => 'custom-blocks' ] ).
 *
 * @param array  $categories The existing categories.
 * @param object $post The current post.
 * @return array The updated array of categories.
 * @author JC Palmes
 */
function acf_blocks_add_block_categories( $categories, $post ) {

	return array_merge(
		$categories,
		array(
			array(
				'slug'  => 'custom-blocks',
				'title' => esc_html__( 'Custom Blocks', 'theme' ),
			),
		)
	);
}
add_filter( 'block_categories_all', 'acf_blocks_add_block_categories', 10, 2 );