Portulaca is great. I don't think it can get too hot for moss rose. My mom used to grow a border filled with it every summer and it was such a riot of color. I've got a hanging basket full now and it has to be watered but it loves the heat.

The agastache doesn't seem to mind the heat; it's been good even with minimal watering. Actually, I think most of my flowers are tolerating the heat better than I am.

Sabal Minor and varieties (Dwarf Palmetto) that is cold hardy here and very drought resistant.

Zinna's esp. thin leaf and profusion zinnia (all self seeded), black eye susan's, coneflowers, coreposis, I have 4 types of agastache that are going like gang busters, most of my roses except my knockouts wow are they have pathetic blooms this year.