I use mainly Protonmail, lately also digging Skiff a lot. It's a shame Startmail doesn't support own domains (yet?).

In the past also tried Tutanota, Mailbox.org, Fastmail, Posteo but never really liked using them.

Thanks for this, actually first time I see this service mentioned anywhere.

Any list of actions you use very much? So I can add when it's useful and I haven't thought about it yet :D