There is mailspring which I have been using for some time - it has a nice modern interface which imho is much better than thunderbird as well as most of the web interfaces of self hosted email. Based on electron though, so ymmv.
+1 for MailSpring! It is easily the best desktop email application I have ever used!
Good chatter I find here of Mailspring--I use it as well. What do y'all think of SparkMail? It's not been brought up here yet. I'm quite fond of it on my mobile device. This came to mind as I looked over Shortwave
Yep - this is what I've been using. Even Nylas Mail, which came before it