Are you in Arkansas? Copper Canyon Daisy & Mexican Marigold Mint both have yellow flowers in fall. I know CCD dies back in the winter, not sure about the mint (since it's an herb I would think it's evergreen).

These both do well in full sun and pretty hot climates.

Amsonia has blue flowers in early summer, then good yellow fall foliage.

Asters and chrysanthemums bloom in fall if cut back several times over the summer. I'm having trouble keeping my Wood's aster from blooming. Other asters (New York or New Engalnd) may be more reliable in fall blooming. I planted a few of the chrysanthemums you get in the fall- some have come back for years for me. Others are annuals- they don't come back.

Check out the perennial sunflowers- some of them will bloom into fall.

Japanese anemone blooms in Sept. here in VA- they're a part sun plant.

I find that if I cut my yarrow back after bloom it will come back and bloom bloom into the fall.

'Happy Returns' daylilly will bloom into the fall.

'Butterfly Blue' scabiosa blooms from spring to fall for me, and will occasionally bloom a bit if we have a warm spell during the winter - but it is tedious to deadhead.

Hope this helps some-

Thank you:):)