On Linux I use Thunderbird for everyday stuff and aerc for git patches. aerc runs in ncurses and supports vim-like keybindings.

On Android I use K-9, but it seems it’s gonna become Thunderbird Android so soon I’ll be using Thunderbird everywhere…

Right now K-9 is the only email client on Android that meets my bar. Efficiency-wise it has just the right amount of pushbuttons to get the job done. Also can we take a moment to appreciate the design? K-9 is peak aesthetic. not that garbage material 2.0 or whatever google calls it. even holo design from android 4.x looks better… (incidentally, this is exactly the case when i used K-9 for the first time, and I remember going “holy shit” at the redesign. K-9, never change)

Thunderbird except on mac I use the Mail client that ships with mac. My favorite between the two is Thunderbird. Idk if I can say it’s the ‘best’ but it’s the one I use. If I need mail in a shell I use mutt.

I use FairEmail on Android and my only gripe really is that the settings menu is so overwhelming! It’s nice to have all the settings though when you can find them.

On desktop, Linux and Windows, I use Thunderbird. My experience connecting this to Nextcloud for the additional Calendaring and Tasks features has not yet been successful but Email works fine. I hope that soon their announced rebuild will drop and I can experience that sure-to-be glory. I may also reconsider K-9 since they have that under their wing now as well.

I’d love a good CLI option. Mutt is archaic but I would still consider it if I demystified it for myself possibly with a nice guide that exists somewhere out there? It just wasn’t too easy to setup in a comfy way last time I tried 🤷‍♂️