The easiest way to have a shared team email is to have one email address (“email@example.com”) and give even one credentials for it. Maybe everyone logs into the same GSuite account. Anyone who is around can deal with incoming email. Maybe you take shifts.
But that’s not particularly elegant. There is lots of room for innovation there. What about real team management with proper permissions? What about multiple inboxes? What about having conversations amongst a team outside of the actual email thread? What about notifying Team members about emails without having to forward it to them?
That’s why we use and love Front at CodePen. It’s a pretty good email client, but the point of it is that it embraces what teams need for email communication, which is a bunch of features that most email clients don’t offer.
I see Polymail is marketed toward team collaboration also. It’s got commenting/mentions that attach themselves to email threads, which is a great feature. The one that is unclear though is assigning emails (they may have it, I just haven’t used it). That’s the feature where an email might come into a main box, but then it’s assigned to a specific person (or persons) so it’s gone from the main incoming box. And that works for any email. For example, I could get an email to firstname.lastname@example.org, which only I have access to, but I could pluck out an individual email to put into the main incoming box or assign to someone else if I wanted to. That’s really thinking through a shared team email experience.