Press Ctrl+J and ask which sent mail is still waiting on a reply, or what is in your promotions. The assistant reads your mailboxes with the app's own tools and shows each one it ran.
A bar above the list sorts mail into Primary, Updates, Promotions and Social, using Gmail's own categories. Move a sender to another category and it stays there.
Schedule a message for Monday morning and it goes out on time while Penguin Mail runs, even from the tray. Sent mail waits a few seconds with an Undo button first.
Hide My Email makes a Gmail plus address for each site you join. When one of them starts getting spam, turn that address off and its mail goes to the Trash.
