Creekside Volcano grows six feet or taller and has the brightest flame colored flowers of just about any dahlia. A bit hard to find these days.
Elks Huckleberry Pie is a cute variegated flower that is easy to grow.
Grysons Yellow Spider is a Dutch dahlia sold in tubers packs at various garden centers.
Lavender Chiffon is a very old variety still being grown as a cut flower. Most people no longer grow it.