I realise it's the opposite of what you are asking, but I still wanted to take the opportunity to mention that there are many advantages with plaintext emails: https://useplaintext.email.

It's okay to allow those who want to use beautiful (I assume it means HTML) emails, but you should always include a plaintext version (it's easy) for those who don't want to/can't read HTML emails.

There was a separate thread about this today: https://news.ycombinator.com/item?id=41928203

Thank you. Didn’t see it.