[ymse]

That's pretty much the tagline of mutt[0].

> All mail clients suck. This one just sucks less.

I've become really fond of notmuch[1]. It's basically a mail database and library with really fast search, tags, and native support for threads. Numerous front-ends exists[2]; I use the bundled emacs client, but have wanted to try out nevermore[3] (it did not work well with Evil last I checked).

0: http://www.mutt.org/

1: https://notmuchmail.org/

2: https://notmuchmail.org/frontends/

3: https://github.com/tjim/nevermore