Touch and hold keys for an array of custom shortcuts.

I know this is already used for custom accents but there are two down diagnal directions not in use. Up diagnal gives capital accent. I think hold key - down diagnal can be used for custom shortcuts like: copy/paste, cut, undo, start selection highlight, numbers, symbols, common emoji, stored text replacements. It doesn't need to be diagnals, maybe just hold and straight down. Each letter should be customizable. Also I never use accents, so I feel it is wasted potential for something more practicle.