Gmelius is like a Swiss army knife for your inbox. The list of features it adds to Gmail is impressive: schedule emails to send later, snooze messages to leave your inbox then return at a designated time, track email opens, add notes to emails, create email templates, block email trackers, automate copying contacts, automatically label outgoing emails, and more. These features all enhance Gmail, but perhaps Gmelius's best feature is the ability to customize Gmail's interface. You can replace the standard paperclip attachment icon, for example, with icons that quickly show what file type is attached. You can disable Google's ads. You can make Gmail always show the To, Cc, and Bcc fields.