You can sync your Follow Up Boss database to MailChimp for mass emails.
This includes contact name, assigned agent, tags, stage, phone, email, price, lead source etc.
Inside MailChimp you can then segment your lists to just email the people you want e.g. past clients only.
Mailchimp is free for up-to 2000 contacts, if you have a larger database you can also check out their pay as you go option.
To connect MailChimp to Follow Up Boss email email@example.com with your MailChimp API Key and which list you would like us to sync with (we'll be making this available in the interface soon).