We’re using this code in the allowed_block_types function here: https://developer.wordpress.org/reference/hooks/allowed_block_types_all/
// Override array to only show widget specific blocks to widget page.
if ( $editor_context->name == 'core/edit-widgets' ) {
$allowed_block_types = array(
'acf/footerlinks',
'acf/footercta',
'acf/footergegevens',
'acf/footerlinksurl',
);
}