The first iPhone famously introduced the soft keyboard, which could change its shape depending on the need. Sometimes it would mean becoming a keypad (for numeric entries), and sometimes something subtler, like introducing a “.com” key to the bottom row, or adding a new column of keys and making the keys a bit more narrow for a few languages that need that.

Bear (the note-taking app) does something interesting: after a button press, it replaces the onscreen QWERTY keyboard with a “funpad” or a “function keypad” (like StreamDeck or Figma Creator Micro). This achieves a similar result to a scrolling toolbar above the keyboard (see: Apple Notes), but in a different way. I haven’t seen anything like this before, and I think it’s really clever and it has worked well for me in practice.

(It also cleverly closes itself upon some actions like introducing a divider, but stays put for bolding, indentation, etc.)