The tie to a terrycloth robe, tied so as to have a knotted end. Not very painful but can give a good thump with great sound. (Besides, it can be a good surprise if the sub has gotten used to being tied with the ties of robes )

A Feather Boa. Obviously this is not a pain inflictor, but with judicious use of restrictive bondage, blindfolding, and build up it can be particuarily cruel on those vulnerable extra sensitive parts. Also, this is a great companion to more intense and traditional tools.

An empty 2 liter soda bottle, cap tight so that the air is hard. Nice sound, mostly harmless, but can sting a bit. Wonderfully humiliating if your sub drank the last drop just before you get home from work.

her favorite vibe or dildo used as a cane is always very nice tease as well.

Just a few things you might have lying about the house that can be used for impromptus. I am sure there are more, but I think My brain fell asleep 400 miles ago.

~LT~