Well wouldn’t you know it, Apple’s been working on a one-handed keyboard for iPhone devices dating back to iOS 8, but it remains unfinished and of course unreleased. You can “unacknowledged” to the list of adjectives, at least officially. Unofficially, we know it exists because there’s a video of the one-handed keyboard in action that developer

Source: Hot Hardware – Secret Unreleased One-Handed iPhone Keyboard Found In Xcode iOS Simulator