Flowers
All flowers add beauty. Their very impermanence reminds the soul of the gift of giving our best into the present moment. One single rose bud, even an old one, can be broken off its stem and its petals scattered in the bath with stunning effect. Irises and lilies, because they have fewer petals, might be better used in a vase in the room. But almost any tiny wild flowers, the leaves of many herbs, like lavender, or fruit trees, like lemons, or even some ground cover, like clover, thrown in to the water, turn an ordinary bath into a special event. Experiment with what you find and do this sometimes when you bath alone as well.