Going from large to small, here are some recommendations of plants unlikely to faint in dry, hot conditions. These are ones I've found both attractive and tough, which you might consider when choosing new plants. Check to see which are appropriate for your climate zone.

Gray birch (Betula populifolia)
Flowering quince (Chaenomeles)
Sumac (Rhus)
Giant Hyssop (Agastache)
Black-eyed Susan (Rudbeckia)
Bluestem grass
Baptisia
Milkweed (Asclepia)
Gaura (Special mention for this plant with small white or pink flowers on wiry stems—it's particularly beautiful and underused.)
Portulaca (A succulent annual with shocking pink and bright orange flowers.)
Curry plant (Helichrysum italicum)
Lamb's ears (Stachys byzantina)
Hens and chicks (Sempervivum tectorum) (The smallest, with its lovable rosettes of succulent leaves.)