Perennials preferring full to mostly sunny conditions usually produce flowers and the plants are generally medium to very tall and usually with bigger flowers. Examples are tickseed (Coreopsis), bee balm (Monarda), sneezeweed (Helenium), perennial sunflowers (Helianthus) or tall phloxes (Phlox paniculata, Phlox maculata, etc.). Most of them are long lived, hardy and proven perennials. You can choose from pure native wildflowers and their nativars.
The more sun they have, the better and more showy they become and many of them are very beneficial for wildlife.
Now, let's brighten your yard!