This is a pretty one:
The yarrow is one of my favorites. I love the lacy leaves and colorful flowers. Also, it’s edible and has several medicinal uses. You can read about it here: http://www.ediblewildfood.com/yarrow.aspx
It’s main purpose is to attract pollinators, especially bees and butterflies. It blooms in spring, summer, and fall, so should be a nice, showy plant.