Customize icon for macro in Quick Access Toolbar Excel 2019

I have 6 macros that I have assigned icons to use in the Quick Access Tool Bar. Currently they are squares in various colors, but I would like to be able to assign a number or letter to each.  That way I would have a clue which macro it refers to without having to hover over it.

1) Can that be developed?

2) Is there a way I can design my own and import it?

Thanks!