I propose adding the ability to select multiple icon sets using standard keyboard and mouse shortcuts:
Shift + Arrow Keys&Shift + Mouse Click: Select adjacent sets.Ctrl + Mouse Click: Select non-adjacent sets.Ctrl + A: Select all sets.Ctrl + I: Invert the current selection.
This feature would also be useful when managing a large number of sets. It makes it easier to perform operations such as moving, deleting, or enabling/disabling (as proposed in a separate feature request).