Also, a varieties of sempervivums, some sedums, lewisia, delopserma, and opuntia fragilis would work out in your zone. But drainage would be 80% gravel on most of these. Not plain soil...
Also yucca gloriosa and filamentosa are options(though id recommend the former and with pruning)
Id say get the variegated gloriosa but that one...might not be hardy enough....
