I don't think there's much, if anything, in the way of App Store guidelines for keyboards except that they do things with the text field the user currently has

I don't think there's much, if anything, in the way of App Store guidelines for keyboards except that they do things with the text field the user currently has highlighted. For instance the app Fantastical comes with a "keyboard" that inputs dates that are open on your calendar[0] and there exist a few rather nonstandard keyboards like Typewise[1]. Absence of features common on Android boards I would guess comes down to those patterns not being familiar to (and thus, not desired by) iOS users or in some cases software patents (there have been a few cases of keyboard devs receiving cease and desist notices from patent holders for using some UI pattern). [0]: https://flexibits.com/img/help/fantastical-ios/en/f3-openings-keyboard-ios.png https://flexibits.com/img/help/fantastical-ios/en/f3-opening... [1]: https://apps.apple.com/us/app/typewise-custom-keyboard/id1470215025 https://apps.apple.com/us/app/typewise-custom-keyboard/id147...