Mark "awaiting reply"
I many mail conversations, you often end up, where you are awaiting a reply on a mail from the recipient. Those kind of mail threads tend to stay in the inbox.
I would like a feature, where I can mark a mail thread as "awaiting reply" and the thread should then be hidden (like in snooze) until I get a reply and at that point, the thread should move back to the inbox.
The even more advanced edition of this idea is, that I can define a "max wait" time, so that if I have not had a reply for say 1 week, then it will move back to the inbox and get my attention again, so I can reach out and poke the recipient for a reply.