One of the things I make is email newsletters. I've used different platforms to produce and manage them, and now I use Ghost (i.e., this site) as my combo blogging and email newsletter platform.
The newsletter I send does not have a set format, and if you subscribe to it, what you get delivered to your inbox will morph and change over time. It also does not have a set release schedule, so there could be times where you get a daily dose of words written by me sent your way, and there may be times where you don't get anything for months. (Usually, a lack of email means I'm taking time to think through something that I feel is important enough to devote significant amounts of attention to.)
Be all that as it may, when I'm in what I think of as "normal" newsletter production mode, I send at least one email a week.