When multiple units are selected, we can use ctrl to deselect individuals from the command card grid. We can use shift to select all units of a particular type.
However the roles of these two keys are swapped in AOE4. In fact many other RTS also use ctrl for “all of a type” and shift for “deselection/add to selection” modifier. So I propose that we could add an option in AOE 2 that would allow us to swap these roles in this game as well.