In the ‘Exports’ tab of your dashboard there is an option to download the list of shifts that volunteers signed up for. Each row has an email associated with that shift -- just filter the list however you’d like, and upload the list to the email client of your choosing.
You can also export the list of volunteers who have signed up for a specific event. You can find a link to export that list on the page for that event in your dashboard.
Stay tuned over the next few months as we work to automate this process.