I'm actually Zone 4/5 but I have some suggestions.
1)Yarrow
2)Rudbeckia
3)Daylilies
4)Iris
5)Asters
6)Autumn Joy sedum
7)Peonies
8)Centaurea montana(Mountain Bluet)
9)Dianthus
10)Echinacea
11)Gaillardia
12)Monarda
13)Catnip
14)Poppies

Enough??

Most penstemons if they are hardy in your zone are quite drought tolerant. Mirabilis multiflora (wild four o'clock) has required little if any water in my garden.

As for bushes and trees, I've found Cercocarpus ledifolius (curl-leaf mahagony) to bed a good drought tolerant shrub.

Native prairie plants tend to be drought-tolerant, not surprisingly.
Some nice ones for the garden are:
Yucca glauca (native to southern prairies); also Y. filamentosa (native to NE US)
Purple prairie clover
coneflowers- Ratibida species
Pasture sage - Artemesia frigida
Sticky geranium (Geranium viscosissimum)
All the things suggested by Plantlady are hardy in your area, and some groups have representatives that are native to these parts (Gaillardia, Monarda, Echinacea).

I need help. I'm in the sixth grade and need help with a science fair project. I'm trying to see which grass is the most drought tolerant. I've collected a variety of sods and only have a month to do my experience. How can I conduct a good scientific experiment inside with heating lamps. Help, help. Stephen.

Stephen, you may want to look under growing under lights forum. This may help you in your endeavor.