My most successful email campaigns ever were for an influencer clothing brand I owned. We had around 100,000 emails in the list, and would only send 2-3 emails every couple months. We would drop new clothing lines about every other month, and the website would only be open for 2-3 days at a time. At any other time, the only thing on the website was an email sign-up. 

Before a drop went live, we would email the list advertising the products that would be available. Then, 60 minutes before the drop went live, we would email out an early-access code that was only available to people who subscribed on the list. Then, depending on stock, we might send a follow up email about 24 hours before the drop closed. This practice resulted in some of the most insane email marketing analytics I’ve ever seen. Like seriously, look at these screenshots: