A bamboo skewer of the type used in the kitchen is quite an interesting sensation toy when it's used on a bound and blindfolded person.
Vibrators make us yearn to touch and be touchedto explore, to discover, to feel, and to love.
These work quite well on nipples, and also on the clitoris. Tie a slipknot in a piece of dental floss and pull it snug on the submissive's nipples.
Remote-controlled vibrators and butt plugs are available at most sex toy stores these days.
Ice is a great all-purpose sex toy that can be used in a number of different ways.
Of course, you can always go with the old standbys--run an ice cube over your lover's body, especially if your lover is blindfolded and/or bound; or place an ice cube in your mouth and run your lips and tongue over your lover's body.