There are three main types of emails you can send to your list: 1. Newsletters and marketing emails. These are emails that are sent one time to your list and provide up-to-date content, news, and offers. 2. Transactional emails. These emails are used in ecommerce and could be things such as order confirmation emails, receipts, invoices, and shipping confirmation emails. 3. Behavioral emails. These are emails that are triggered based on subscriber actions, such as welcome emails when a user joins your list, upsell/cross-sell emails, post-purchase review emails, re-engagement emails, or free trial expiration emails.