https://wordpress.org/plugins/distributionlist/
Distribution List to send emails to members in your Connections Business Directory plugin
This is a very basic plugin that picks ‘Preferred‘ emails from the ‘Connections Business Directory’ Plugins table where member status is not ‘Unlisted‘ and sends mail out using the PHP mail function.
Based on your server ‘Max_Execution_Limit’ of 30 seconds, the plugin is designed to send 12 emails per minute.
This plugin is suitable for small list and can support up to 500 users