public function toOptionArray()
    {
        /** @var $collection \Magento\Email\Model\ResourceModel\Template\Collection */
        if (!($collection = $this->coreRegistry->registry('config_system_email_template'))) {
            $collection = $this->templatesFactory->create();
            $collection->load();
            $this->coreRegistry->register('config_system_email_template', $collection);
        }
        return $this->emailConfig->getAvailableTemplates();
    }