I am trying to think.......I believe you can grow anything here that is rated for our Z6. Of course, some things will do better than others. For instance, if a plant likes cooler weather in the summers, it probably won't be your best choice.
Snaps are supposed to be that way, but they do great for me.
Campanulas.....I am just trying, so don't know how they will do.

I would say try anything. I like to mix in lots of annuals for color all season, zinnias, cosmos, bachelor buttons, marigolds, etc.

Good luck and welcome to Missouri.

I've been living in the Ozarks, and gardening, for quite a while and have a few favorites in the flowers. Sunset Cosmos are a "no fail" and actually reseed themselves several times during the Summer, sometimes 3-4 times if the rain happens often enough. Gaillardia, both annual and Perenial types are really great! French Marigolds bloom nonstop up to and sometimes thru several frosts. For the heat of the summer, I like the Daturas, and Tithonias[ Mex. Sunflower] and , of coursde, Daylillys of all kinds and colors planted everywhere. Strong

Don't forget echinacea (coneflowers) and other natives. I haven't had much trouble at all. See what your local nurseries have and give them a try.

I also like the Lily and planted quite a few bulbs. The Orientals are my favorite the smell is awsome. So what is in my garden are roses(shrub type), tulips, daffys, lilies, butterfly bush, lily of the valley, coneflowers, bee balm, hosta, cardnal flower, daylilies, iris, rock garden with hens & chicks, just to name a few. Then there are lots of shrubs that grow here and annuals. I try to plant lots of things for Humminbirds as there are quite a few in my area. Nancy

Hosta and ferns for the shade also fragrant deciduous azaleas. Phlox, bee balm, daylilies, cone flower,wall flower, sweet rocket, larkspur, clematis, poppies, virginia blue bells, cat mint, crepe myrtle, fragrant winter honeysuckle and fragrant viburnum, oriental lilies (I put most in pots because something eats them). Spring bulbs of most kinds. I don't have much luck with allium or stinky fritillaria. For spring pansy, viola and creeping phlox. Crabapple, dogwood, red bud trees.. . .and more