Today I needed to get a section from a Markdown document into an HTML email, quickly. It was a long list of URLs and I wanted them to render as hyperlinks. I use Markdown for everything, so I was slightly embarrassed to be stumped by this.
The solution: use your text editor’s Markdown preview functionality and just copy and paste from the preview. Works both in Thunderbird and in browser based email.
Yes, there are other solutions, like markdown-here and various extensions in Thunderbird. But extensions are clutter and I prefer to do without them if I can.