Yet another solution to this problem — Airmail 3. Airmail 3 is a highly configurable email client and offers the opportunity to specify what Mailbox is mapped as the Inbox, Starred, Important, Drafts, Spam, Trash, All Mail, Archive, Sent, To Do, Memo, Done, and Snooze. And if you have multiple accounts the settings are unique for each account.

"What is the Snooze mailbox?", I asked when I saw it. Snooze is a feature where messages can be tagged manually or even by a rule to "snooze" until Later Today, Tomorrow, This Evening, This Weekend, or Next Week and it will go to the Snooze mailbox only to pop back up at whatever time was specified for each of the Snoozes.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein