The Thunderbird add-on that lets you compose directly in HTML is fun for this kind of thing. You can also abuse those signature-maker site HTML signatures into full emails, tightly composed.
I also think PDF newsletters are cool if you're doing anything people might like to store. I have been trialing Textmaker 2018 for this in Linux and it will do most desktop publishing stuff like linked text frames really easily, plus export to HTML, pdf, and epub.
I also think PDF newsletters are cool if you're doing anything people might like to store. I have been trialing Textmaker 2018 for this in Linux and it will do most desktop publishing stuff like linked text frames really easily, plus export to HTML, pdf, and epub.