Hmm i did a variation on this once.
Had my sub pick out 10 items for her punishment and line them up on the coffe table (severe punishment).

She didnt pick out a single thing not useful for causing pain or discomfort. But had she done so id prolly have figured out a way of abusing said item anyways, or just plain skipped it adding punishment for failing.

As for the OP excellent idea. Dont really have to be for actual use just nice to have for scaring her a little later on.

As for denuseri youll sleep chained to the doghouse in the yard tonight and well discuss you revised list tomorrow... (or something to that effect)